1. Water Systems Operator Certiﬁcations

This chapter summarizes the elements of the water operator certiﬁcations including, the legal

requirements (drivers), operational activities, levels of certiﬁcations, qualiﬁcations and eligibility

requirements, exams and certiﬁcation renewals.

•

Federal law requires any person operating a water treatment plant to be certiﬁed. Addi-

tionally, water systems are required to utilize only certiﬁed distribution operators to make

decisions related to activities in the water distribution systems.

•

California Law under Title 23 stipulate that except for a person certiﬁed by the Department

of Health Services as a water treatment plant operator, no person shall operate a water recy-

cling treatment plant unless that person has been certiﬁed by the division as a wastewater

treatment plant operator or operator-in-training at a grade appropriate for the class of plant

being operated.

•

The California State Water Quality Control Board is responsible for the testing and certiﬁ-

cation of water treatment and water distribution operators throughout the state of Califor-

nia.

California’s State Water Resources Control Board’s (SWRCB’s) Drinking Water Operator

Certiﬁcation Program (DWOPCP) is responsible for under its Drinking Water Operator

Certiﬁcation Program (DWOCP) is responsible for the testing and certiﬁcation of water

treatment and water distribution operators throughout the state of California. The test-

ing and certiﬁcation requirements meet the guidelines established by the United States

Environmental Protection Agency (EPA) as required by the Safe Drinking Water Act.

Similar to the drinking water operator certiﬁcation,SWRCB’s Wastewater Operator Certiﬁ-

cation program (WWOCP) administers Wastewater Treatment Plant Certiﬁcation examina-

tions, certiﬁcations (Grades I to V), and certiﬁcation renewals.

•

Chapter 1. Water Systems Operator Certiﬁcations

•

The CA-NV AWWA currently offers voluntary Advanced Water Treatment Operator

(AWTO) certiﬁcations for water and wastewater operators to meet the demand for highly

skilled and certiﬁed advanced water treatment operators continues to grow as more ad-

vanced treatment facilities come online.

1.1 Operational Activities

California laws stipulate that water systems shall utilize only certiﬁed operators to make deci-

sions addressing the following operational activities:

1.1.1 Drinking Water Treatment:

Water treatment operators work in water treatment plants where water from wells, rivers, streams,

and reservoirs is treated and distributed to customers. Water treatment plant operators typically

do the following:

• Add chemicals, such as ammonia, chlorine, or lime, to disinfect water or other liquids

• Inspect equipment on a regular basis

• Monitor operating conditions, meters, and gauges

• Collect and test water and sewage samples

• Record meter and gauge readings, and operational data

• Operate equipment to purify and clarify water, or to process or dispose of sewage

• Clean and maintain equipment, tanks, ﬁlter beds, and other work areas

• Stay current on environmental laws and regulations

• Ensure safety standards are met

1.1.2 Water Distribution:

•

Water distribution operators are responsible for the safe and efﬁcient operation of water

pumps, valves, and other equipment. They monitor gauges and meters to ensure that water

is being distributed in a timely manner and at appropriate pressures.

•

Water distribution operators may also be tasked with maintaining or repairing any equip-

ment that breaks down during their shift. This could include anything from replacing parts

on pumps to ﬁxing leaks in pipes or hoses.

• Water distribution operators typically do the following:

– Install, tap, re-line, disinfect, test and connect water mains and appurtenances.

– Shutdown, repair, disinfect and test broken water mains.

– Oversee the ﬂushing, cleaning, and pigging of existing water mains.

– Pull, reset, rehabilitate, disinfect and test domestic water wells.

–

Stand-by emergency response duties for after hours distribution system operational

emergencies.

– Drain, clean, disinfect, and maintain distribution reservoirs.

Water systems shall utilize either certiﬁed distribution operators or treatment operators that have

1.1 Operational Activities

been trained to make decisions addressing the following operational activities:

•

Operate pumps and related ﬂow and pressure control and storage facilities manually or by

using a system control and data acquisition (SCADA) system.

Maintain and/or adjust system ﬂow and pressure requirements, control ﬂows to meet con-

sumer demands.

Determine and control proper chemical dosage rates for wellhead disinfection and distribu-

tion residual maintenance.

• Investigate water quality problems in the distribution system.

1.1.3 Wastewater Treatment:

Federal law stipulates no person shall operate a wastewater treatment plant without a valid, unex-

pired, State Water Board-issued operator, provisional operator, or operator-in-training certiﬁcate

at a grade level appropriate for the class of wastewater treatment plant being operated.

Wastewater operators typically do the following as part of their job responsibilities:

• Operate and maintain the wastewater treatment plant and collection systems.

•

Operate and adjust controls on treatment plant equipment and machinery, such as valves,

pumps, and motors.

• Read and interpret meters and gauges

• Regulate plant efﬂuent

•

Monitor, repair, and maintain wastewater system lift stations; remove debris; disassemble

and clean pumps; perform minor repairs when necessary. Locate problems and operate

sewer cleaning equipment to clear blockages

•

Performs routine maintenance and minor repairs on plant equipment, system equipment,

facilities, distribution system, and collection system.

• Maintaining plant records and preparing monthly and quarterly reports.

•

Perform all aspects of sampling, monitoring, and testing required to maintain compliance

with Federal, State, and Local regulations governing the wastewater treatment process,

stormwater, and sludge management.

1.1.4 Advanced Treatment/Water Reuse:

The Advanced Water Treatment Operators (AWTO) perform a full range of duties associated

with operating and maintaining water treatment systems and equipment used for Advanced Water

Treatment for water reuse. AWTO typically do the following as part of their job responsibilities:

•

Operate, monitor, and maintain AWT processes, such as membrane systems and advanced

oxidation.

AWTOs have an advanced understanding of technologies and regulations pertinent to the

end uses of treated water; such as recycled water, potable water, and potable water reuse.

At the supervisor and management level, maintain regular communication with regulatory

agencies and ensure permit compliance.

• Responsibility for preparing and submitting regulatory reports.

Chapter 1. Water Systems Operator Certiﬁcations

1.2 Qualiﬁcations and Eligibility

1.2.1 Treatment

Grade

Minimum Qualiﬁcations for Examination

High School Diploma / GED Equivalency*.

Eligibility Criteria for Certiﬁcation

Successful completion of the Grade T1 examination within

the three years prior to submitting certiﬁcation application.

High School Diploma / GED Equivalency*

AND

One 3-unit (or 36-hour) course of specialized training covering

the fundamentals of drinking water treatment.

Successful completion of the Grade T2 examination within

the three years prior to submitting certiﬁcation application.

Successful completion of the Grade T3 examination within the

three years prior to submitting certiﬁcation application

AND

At least one year of operator experience working as a certiﬁed

T2 operator at a T2 facility or higher. This may be substituted

High School Diploma / GED Equivalency*

AND

Two 3-unit (or 36-hour) courses of specialized training

that include at least one course in drinking water treatment and a with (3) below.

second coursein either drinking water treatment, distribution,

or wastewater treatment.

AND

At least one additional year of operator experience working as a

certiﬁed treatment operator. This may be substituted with

(1), (2), or (4) below.

Successful completion of the Grade T4 examination within the

three years prior to submitting the certiﬁcation application

AND

At least one year of operator experience working as shift

or chief operator, while a certiﬁed T3 operator at a T3

facility or higher. This may be substituted with (3) below.

AND

At least three additional years of operator experience

working as a certiﬁed treatment operator. This may be

substituted with (1) or (4) below.

Current T3 certiﬁcation

AND

Three 3-unit (or 36-hour) courses of specialized training that

include at least two courses in the fundamentals of drinking

water treatment and a third course in either

drinking water treatment, distribution, or wastewater treatment.

Successful completion of the Grade T5 examination within the

three years prior to submitting the application for certiﬁcation

AND

At least two years of operator experience working as a shift or

chief operator, while a certiﬁed T4 operator at a T4 facility or

higher. There are no substitutions.

Current T4 certiﬁcation

AND

Four 3-unit (or 36-hour) courses of specialized training that

include

at least two courses in drinking water treatment and two

additional courses in either drinking water treatment,

distribution,or wastewater treatment.

AND

At least three additional years of operator experience working

as a certiﬁed treatment operator. This may be substituted with

(1) or (4) below.

Table 1.1: Water Treatment License Exams - Qualiﬁcations and Eligibility

"*High School Diploma/GED equivalency for Grades 1 and 2 ONLY can be fulﬁlled with either successful completion of Basic Small Water Systems Operations course

provided by the Department OR 1 year as an operator of a facility that required an understanding of a chemical feeds, hydraulic systems, and pumps."

"Experience substitutions for certiﬁcation, as referenced above.

1. A relevant degree earned at an accredited academic institution may be substituted as follows:

a) Associate’s Degree or Certiﬁcate in Water or Wastewater Technology that includes at least 15 units of physical, chemical, or biological science may be used

to fulﬁll 1 year of operator experience.

b) Bachelor’s Degree in engineering or in physical, chemical, or biological sciences (e.g Biology, Chemical Engineering, Chemistry, Civil Engineering,

Environmental Engineering, Microbiology, Public Health, or Sanitary Engineering) may be used to fulﬁll 1.5 years of operator experience.

c) Master’s Degree in the above mentioned ﬁelds in (b) may be used to fulﬁll 2 years of operator experience.

2. A certiﬁed operator may substitute, on a day-for-day basis, experience gained while working with lead responsibility for water quality related projects of research.

3. If an applicant has a Bachelor’s or Master’s of Science degree, completion of a comprehensive operator training program, pursuant to Section 63800(h), may be

substituted for the required experience.

4. Experience gained as a certiﬁed wastewater treatment operator may be used to substitute up to 2 years of the experience requirement. Wastewater treatment operator

experience is credited on a two-for-one basis (i.e. 2 months in wastewater=1 month in drinking water)."

1.2 Qualiﬁcations and Eligibility

1.2.2 Distribution

Minimum Qualiﬁcations for

Eligibility Criteria for

Certiﬁcation

Grade

Examination

Successful completion of the Grade D1 examination within

the three years prior to

High School Diploma / GED Equivalency*

submitting certiﬁcation application.

High School Diploma / GED Equivalency*

AND

One 3-unit (or 36-hour) course of specialized training covering

the fundamentals of water supply principles.

Successful completion of the Grade D2 examination within

the three years prior to submitting certiﬁcation

application

Successful completion of the Grade D3 examination within

the three years prior to submitting certiﬁcation application

AND

At least one year of operator experience working as a certiﬁed

D2 operator for a D2 system or higher

AND

At least one additional year of operator experience working

as a distribution operator. This may be substituted with (1)

or (2) below.

Current D2 Certiﬁcation

AND

Two 3-unit (or 36-hour) courses of specialized training that

includes at least one course in the fundamentals of water supply

principles and a second course in either drinking water

distribution, treatment, or wastewater treatment.

Successful completion of the Grade D4 examination within the

three years prior to submitting the application for certiﬁcation

AND

Current D3 certiﬁcation

AND

At least one year of operator experience working as a

certiﬁed D3 operator for a D3 system or higher

AND

Three 3-unit (or 36-hour) courses of specialized training

that includes at least two courses in the fundamentals of water supply

principles and a third course in either drinking water distribution,

treatment, or wastewater treatment.

At least three additional years of operator experience working

as a distribution operator. This may be substituted with (1)

or (2) below.

Successful completion of the Grade D5 examination within

the three years prior to submitting the application for

certiﬁcation

Current D4 certiﬁcation

AND

Four 3-unit (or 36-hour) courses of specialized training

that includes at least two courses in the fundamentals of water

supply principles and two additional courses in either

drinking water distribution, treatment, or wastewater treatment.

At least two years of operator experience working as a

certiﬁed D4 operator for a D4 or D5 system

AND

At least three additional years of operator experience

working as a distribution operator. This may be substituted

with (1) or (2) below.

Table 1.2: Distribution License Exams - Qualiﬁcations and Eligibility

High School Diploma/GED equivalency for Grades 1 and 2 ONLY can be fulﬁlled with either successful completion of Basic Small Water Systems Operations course provided

by the Department OR 1 year as an operator of a facility that required an understanding of a piping system that included pumps, valves, and storage tanks.

"Experience substitutions for certiﬁcation, as referenced above.

1. A relevant degree earned at an accredited academic institution may be substituted as follows:

(a) Associate’s Degree or Certiﬁcate in Water or Wastewater Technology that includes at least 15 units of physical, chemical, or biological science may be used

to fulﬁll 1 year of operator experience.

(b) Bachelor’s Degree in engineering or in physical, chemical, or biological sciences (e.g. Biology, Chemical Engineering, Chemistry, Civil Engineering,

Environmental Engineering, Microbiology, Public Health, or Sanitary Engineering) may be used to fulﬁll 1.5 years of operator experience.

2. A certiﬁed operator may substitute, on a day-for-day basis, 1 additional year of operator experience working as a distribution operator with experience gained while

working with lead responsibility for water quality or quantity related projects or research."

Chapter 1. Water Systems Operator Certiﬁcations

1.2.3 Wastewater

CERTIFICATION QUALIFYING EXPERIENCE

PATH

EXAMINATION EDUCATION REQUIREMENTS

REQUIREMENTS

GRADE I

High school diploma or equivalent and 6 educational pts

High school diploma or equivalent and 9 educational pts

and

1 year of full-time qualifying experience

GRADE II

18 months of full-time qualifying experience as a Grade I

operator

2 years of full-time qualifying experience

High school diploma or equivalent and 12 educational pts

Associate’s degree, a higher degree, or a minimum of

60 college semester units, including a minimum of 15

semester units of science courses

1 year of full-time qualifying experience

GRADE III

High school diploma or equivalent and 12 educational pts

and

3 years of full-time qualifying experience as a Grade II

operator

4 years of full-time qualifying experience

High school diploma or equivalent and 18 educational pts

Associate’s degree or a minimum of 60 college semester

units,including a minimum of 15 semester units of

science courses

Bachelor’s degree or a higher degree, including a

minimum of 30 semester units of science courses

2 years of full-time qualifying experience

1 year of full-time qualifying experience

6 years of full-time qualifying experience

and

GRADE IV

High school diploma or equivalent and 32 educational

points

Associate’s degree or a minimum of 60 college semester

units, including a minimum of 15 semester units of science and

courses

4 years of full-time qualifying experience

3 years of full-time qualifying experience

Bachelor’s degree or a higher degree, including a minimum

of 30 semester units of science courses

and

Valid registration as a chemical, civil,

or mechanical engineer issued by the California Board

for Professional Engineers and Land Surveyors or by

another state, territory, or Indian tribe

and

2 years of full-time qualifying experience

10 years full-time qualifying experience

GRADE V

High school diploma or equivalent and 48 educational

points

and

Associate’s degree or a minimum of 60 college semester

units, including a minimum of 15 semester units of science and

courses

6 years of full-time qualifying experience

5 years of full-time qualifying experience

Bachelor’s degree or a higher degree, including a mini-

mum of 30 semester units of science courses

Valid registration as a chemical, civil, or mechanical

engineer issued by the California Board for Professional

Engineers and Land Surveyors or by another state, a

territory, or an Indian tribe

and

4 years of full-time qualifying experience

Table 1.3: Wastewater Operator License Exams Requirements

•

1,800 hours of qualifying experience as an Operator-In-Training (OIT) at a wastewater treatment plant (WWTP) is required

to become a certiﬁed operator. The 1,800 OIT hours counts as one year of full-time qualifying experience.

• OIT applicants must submit a copy of a high school diploma or equivalent and six educational points.

• Volunteer, part-time, full-time and overtime hours qualify.

• OIT hours are not grade level speciﬁc and OIT experience does NOT expire.

•

OIT certiﬁcates are good for three years from the date of issuance and can be renewed. To renew an OIT certiﬁcate, an

applicant must have taken and passed a Wastewater Exam within the last four years.

1.3 Expected Range of Knowledge

1.2.4 Advanced Water Treatment or Water Recycle

Grade 3

•

Possess a current state issued Drinking Water Treat-

ment Operator Certiﬁcation or Wastewater Treatment

Plant Operator Certiﬁcation, Grade III or higher

•

Successful completion of AWTO Grade 3 Exam

(AWT3TM)

Grade 4

• Possess a current AWT3 certiﬁcation

•

Successful completion of AWTO Grade 4 Exam

(AWT4TM)

2 years of experience with one or more AWT pro-

cesses (see Table 1). Retroactive experience prior to

AWT3 certiﬁcation may be included

Grade 5

• Possess a current AWT4 certiﬁcation

•

Successful completion of AWTO Grade 5 Exam

(AWT5TM)

•

3 years of experience to include 2 years of experience

in at least one AWT process and 1 additional year

with at least 2 AWT processes in a single treatment

train (see Table 1). Retroactive experience prior to

AWT4 certiﬁcation may be included.

Table 1.4: Advanced Water Treatment Certiﬁcation Requirements

Exam Fee

Reexamination

Fee

Application Fee

D1 & T1

D2 & T2

D3 & T3

D4 & T4

$50

$65

$100

$130

$155

$50

$30

$45

$70

$95

$120

$30

$45

$70

$95

$120

$70

$80

$120

$140

$95

$125

$170

$190

D5 & T5

WW Grade I

WW Grade II

WW Grade III

WW Grade IV

WW Grade V

$65

$100

$130

$155

$250 - for Members of CA-NV AWWA, CWEA or both

$350 - for Non-Members of either association

AWWA - AWTO Grades III - V

Table 1.5: Exam and application fees

1.3 Expected Range of Knowledge

1.3.1 Treatment

The Expected Range of Knowledge for Drinking Water Treatment Exam is provided in Appendix

1.3.2 Distribution

The Expected Range of Knowledge for Drinking Water Distribution Exam is provided in Ap-

pendix B.

Chapter 1. Water Systems Operator Certiﬁcations

1.3.3 Wastewater

Details for each of the Grades I-V Wastewater Operator License Exams is provided in Appendix

1.4 Certiﬁcation Requirements

1.4.1 Treatment

•

Treatment systems are classiﬁed as T1-T5, according to a point system that takes into

account various source water characteristics, maximum capacity and treatment techniques.

Appendix E provides details on the classiﬁcation of water treatment facilities.

Total Points

Less than 20

20 through 39

40 through 59

60 through 79

80 or more

Class

Table 1.6: Water Treatment Facility Class Designations

•

Any person operating a water treatment plant is required to possess a valid, unexpired

water treatment operator certiﬁcate of appropriate grade.

The certiﬁcation requirements of the Chief Treatment Plant Operator and that of the Shift

Operator - persons in responsible charge of the water treatment plant, are required to pos-

sess a valid, unexpired water treatment operator certiﬁcate equal to or greater than the

classiﬁcation of the water treatment plant.

Total Points

Minimum Certiﬁcation of

Minimum Certiﬁcation

Class

Chief Operator

of Shift Operator

Table 1.7: Minimum Certiﬁcation Requirements for Chief and Shift Operators

1.4 Certiﬁcation Requirements

1.4.2 Distribution

• Distribution systems are classiﬁed as D1 to D5 by population served and system complex-

ity. The population categories are:

Class Population Served

≤1,000

1,001 - 10,000

10,001 - 50,000

50,001 - 5 million

≥5 million

Table 1.8: Distribution Systems Class Designations

•

Distribution systems can be upgraded one level due to complexity, using a point system

which takes into account: number of pressure zones, storage reservoirs and uncovered

storage reservoirs, treatment, the size of the largest pump utilized, and customers with a

nonpotable water supply connection.

•

A person who operates a water distribution system shall possess a valid, unexpired water

distribution operator certiﬁcate of the appropriate grade in accordance with the regulations

adopted pursuant to Section 106910.

A person who is in responsible charge of the water distribution system shall possess a

valid, unexpired water distribution operator certiﬁcate equal to or greater than the classiﬁ-

cation of the water distribution system.

Distribution System

Minimum Certiﬁcation of

Minimum Certiﬁcation

Classiﬁcation

Chief Operator

of Shift Operator

Table 1.9: Minimum Certiﬁcation Requirements for Chief and Shift Operators

Chapter 1. Water Systems Operator Certiﬁcations

1.4.3 Wastewater

•

All operators shall possess at least a valid Grade I certiﬁcate, a valid provisional operator

certiﬁcate, or a valid operator-in-training certiﬁcate.

Wastewater treatment plants are classiﬁed as Class I to V based upon the plant design ﬂow

and treatment process.

For each plant class, WWOCP sipulates that the Chief plant operator and designated

operator-in- charge shall possess a valid operator certiﬁcate at a grade level at least equiva-

lent as provided to the following:

Class Treatment Process

Design Flow (MGD)

All

1 or less

Pond

Primary

Greater than 1 through 5

1 or less

All

Greater than 5 through 20

Greater than 1 through 10

5 or less

Bioﬁltration

Extended Aeration

Primary

Bioﬁltration

Activated Sludge

Tertiary

III

1 or less

Primary

Greater than 20

Greater than 10 through 30

Greater than 5 through 20

Greater than 1 through 10

Greater than 30

Greater than 20

Greater than 10

Bioﬁltration

Activated Sludge

Tertiary

Bioﬁltration

Activated Sludge

Tertiary

Table 1.10: Wastewater Treatment Plant Classiﬁcation

1.4.4 Advanced Water Treatment

Per California laws, a water treatment plant operator may operate a water recycling treat-

•

ment plant at a grade level appropriate for the class of wastewater treatment plant being

operated.

Wastewater Treatment

Plant Classiﬁcation

Water Treatment Plant

Operator Certiﬁcate

Wastewater Treatment Plant

Operator Certiﬁcate

Grade I

III

Grade II

Grade III

Grade IV

Grade V

Table 1.11: Certiﬁcate Requirements for Water Recycling Treatment Plants

1.5 Certiﬁcation Renewal

1.5.1 Treatment and Distribution

•

Certiﬁcation must be renewed every 3 years, or at least 120 days, but not more than 180

days, before the expiration date.

The continuing education requirements to renew a California water operator certiﬁcate are

as follows:

There are no continuing education requirements for wastewater operator certiﬁcation

renewal.

Exam

D1, T1

D2, T2

D3, T3

D4, T4

D5, T5

Required Contact Hours

12 hours

16 hours

24 hours

36 hours

Up to 25% of contact hours can be fulﬁlled by completing safety training.

Table 1.12: Certiﬁcate renewal contact hours requirements

Triennial renewal

Discounted

certiﬁcation and

renewal

D1 & T1

D2 & T2

D3 & T3

D4 & T4

D5 & T5

$70

$80

$120

$140

$150

$55¹

$60¹

$90¹

$105¹

$115²

WW Grades I - V

For operators with both a water treatment and water

distribution certiﬁcates

For operators with both a wastewater and water

treatment/distribution certiﬁcate

Table 1.13: Certiﬁcate renewal fees

Chapter 2

Water Properties and Sources . . . . . . . . 25

Properties of water

Water use

2.1

2.2

2.3

2.4

2.5

Water Supplies

Water Sources

Water Rights in Claifornia

Chapter 2. Water Properties and Sources

2. Water Properties and Sources

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams

Ability to measure well depth

Ability to recognize potential sources of contamination

Knowledge of the hydrologic cycle

Knowledge of security procedures/measures

Ability to calculate draw down

Ability to recognize abnormal pH levels of water in a distribution system

Ability to recognize abnormal turbidity levels in a distribution system

Knowledge of normal pH range in drinking water

Knowledge of the impacts of high nitrate concentrations in a distribution system

Knowledge of the meaning of high levels of turbidity in a distribution system

Knowledge of contamination sources in a well

Knowledge of water storage contamination sources

Ability to measure the water depth in a well

Knowledge of water depth measurement techniques

Knowledge of cone of depression

Knowledge of recovery time

Knowledge of static and pumping water level

Knowledge of water table ﬂuctuations

Knowledge of well components and terms

Knowledge of well protection

Knowledge of zone of inﬂuence

Knowledge of proper installation of a sanitary seal on a well

Knowledge of the vulnerability assessment

Knowledge of well location requirements

Knowledge of the chemical components of groundwater

Ability to calculate speciﬁc yield

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams (Continued)

Knowledge of long-term water availability

Knowledge of sanitary survey requirements

Knowledge of the characteristics of aquifers

Knowledge of proper gravel packing and screen depth

Knowledge of well abandonment procedures and permit requirements

Ability to estimate future water needs

Knowledge of capital improvement/capital replacement requirements

Knowledge of permit requirements

Water Treatment System Operator License Exams

Ability to recognize abnormal well operations

Ability to recognize potential security risks

Ability to recognize potential sources of contamination in surface water

Ability to recognize the inﬂuence of surface water on a groundwater source

Knowledge of ﬂow measurement devices

Knowledge of potential microbial and chemical contamination sources in groundwater and sur-

face water

Knowledge of the characteristics of aquifers

Knowledge of the hydrologic cycle

Knowledge of visual signs of contamination in a surface water reservoir

Knowledge of well components

Knowledge of well depth measurement procedures

Knowledge of well disinfection procedures

Knowledge of well drawdown measurement techniques

Knowledge of waterborne pathogens

Ability to interpret water quality reports

Ability to discriminate between normal and abnormal conditions of a surface water reservoir

Ability to recognize hydrological changes

Knowledge of how reservoir intake level effects water quality

Knowledge of the effects of seasonal changes on water reservoirs

Knowledge of surface water reservoir stratiﬁcation

Ability to recognize head loss across an intake screen

Knowledge of groundwater treatment procedures

Ability to interpret historical water use data

Chapter 2. Water Properties and Sources

2.1 Properties of water

•

Water is one of the most abundant and common materials on earth. It covers 70 per- cent

of the surface of the earth as water and ice.

Water makes up 60-75% of human body weight. A loss of just 4% of total body water

leads to dehydration, and a loss of 15% can be fatal. A person could survive a month

without food but wouldn’t survive 3 days without water .

•

Even though most other planets have water in some form, the earth is the only planet in

the solar system that contains water in all its common forms (gas, liquid, solid). Others

have ice, but only the earth has an abundance of this miraculous substance in the proper

temperature range to support life.

Its chemical formula, H₂O, indicates that each of its molecules contains one oxygen and

two hydrogen atoms. The much larger oxygen atom is connected by covalent bonds to

each of the two hydrogen atome. The hydrogen atoms are attached to the oxygen atom at

an angle of 104.45^◦

Even though the water molecule is overall neutral, its bent shape results in the accumula-

tion of positive charge near the oxygen end and negative charge near the hydrogen. This

differential in charges makes the water molecule polar - like a magnet and bestows it

unique properties.

The polarity and molecule size of water imparts it a unique property of being able to dis-

solve a very wide range of minerals, chemicals and gases which makes it indispensable

for the existence of lifeforms and a very critical element of our day-to-day life. However,

many of the substances dissolved in water must be removed during treatment to make

water safe to drink.

•

Nonpolar substances such as oils, fats, and many organic compounds do not dissolve as

easily in water.

Figure 2.1: Water Molecule

•

Pure water will not conduct electrical current. But when soluble salts such as sodium

chloride (NaCl), calcium carbonate (CaCO₃) are present in water, water will conduct

electricity as these salts ionize - break into its constituent positive and negative charged

2.2 Water use

particles the water, and the charged ions make water to conduct electrical current.

NaCl ↔ Na⁺+Cl⁻

•

The more ions there are in a solution, the more easily the current ﬂows. The ability to

conduct electrical current is called conductivity and can be used to indirectly estimate the

amount of total dissolved solids in the water.

The boiling of water - 100 deg. C or 212 deg. F and its melting/freezing point - 0 deg. C or

32 deg. F is very high compared to similar molecules and it is the only natural substance

found in all three physical states at the temperatures that naturally occur on Earth.

Most other substances become more dense as they cool. However, ice is less dense than

water which makes ice ﬂoat on water.

•

Ice on the water surface insulates the water below preventing it from freezing and allowing

for ﬁsh and other life form to survive and allows for the movement of animals who live in

these cold habitats.

•

As water cools, its density increases upto 4^◦C after which it gets less dense as it is cooled

further.

The changing density of water is responsible for turnover of a lake during fall. When the

surface water cools, the cold water becomes more dense than the warm water below so the

cold water sinks to the bottom and warm water rises to the top. When lakes are used as the

source water for water treatment plants, turnover can cause abrupt changes in the quality of

raw water.

•

It needs a lot of energy to make the water warmer or cooler (high Speciﬁc Heat) which

allows for keeping the temperature of water bodies such as oceans, rivers, ponds more or

less constant despite the heat from the sun.

Water molecules stick together well because of its high surface tension - which allows for

water to rise up in tubes through capillary action. This capillary action allows for plants to

draw water along with nutrients from the ground.

2.2 Water use

Besides it being needed for basic sustenance of all living beings, water is vital element for

•

the world economy and sustenance of the human society in various ways including:

– As a food source - ﬁshing

– For commerce - shipping, trade and transportation

– For recreation - swimming, skiing, surﬁng etc.

• Breakdown of global freshwater use:

70% is used for agriculture

19% is used by industries, and

11% is for municipal use

Chapter 2. Water Properties and Sources

2.3 Water Supplies

•

Civilizations have always formed near water sources - on the banks of rivers. Ancient

Egyptians - on the Nile, Mesopotamians in the Fertile Crescent on the Tigris/Euphrates

rivers, Ancient Chinese on the Yellow River, and the Ancient India on the Indus.

The water on our Earth today is the same water that has been here for nearly 5 billion

years.

•

Water molecules were formed in interstellar space by chemical reactions between hydro-

gen molecules and oxygen-bearing molecules such as carbon monoxide and the Earth

inherited its water from asteroids and comets crashing into it.

The only thing that changes is the form that water takes as it travels through the water

cycle.

•

On Earth, water is the only substance that can occur naturally in its three states of matter -

gas, liquid and solids, circulates naturally through its ﬁve principal realms:

– Oceans

– Atmosphere

– Lakes and rivers

– Icecaps and glaciers

– Underground

This is the planetary Water Cycle.

• Elements of the water cycle include:

– Transpiration - process by which plants lose water as vapor out of their leaves.

–

Evaporation - conversion of water in oceans, rives and lakes into vapor by the heat

from the sun

Evapotranspiration is the combined processes of evaporation and transpiration - the

movement of water from oceans or land to the atmosphere.

Condensation - cooling of water vapor in the upper layer of earths atmosphere into

liquid water in the form of clouds

– Precipitation - discharge of the water bearing clouds as rain, hail, sleet or snow.

– Inﬁltration - movement of water from surface to soil.

• Life on earth is dependent on the Earth’s water cycle

•

A watershed is the area of land, where all of the water that falls in it and drains off of it

into to a common outlet which could be a one or combination of water bodies such as a

river, lake or underlying ground water.

The natural features including - mountains, trees, shrubs, grasses, and man-made features

such as urban area, industries, wastes and water discharges affect the quality of the water

in or from the watershed.

Watersheds are important sources of drinking water, as well as a habitat for many aquatic

species. Healthy watersheds with intact native vegetation and wetlands provide important

functions such as water puriﬁcation, ﬂood control, nutrient recycling, and groundwater

2.3 Water Supplies

Figure 2.2: Water Cycle

(Credit:David Cain/NWS)

recharge.

•

Water covers about 71% of Earth’s surface. The distribution of Earth’s water is provided in

the below table.

97% of the Earth’s water can be found in our ocean and freshwater is only 2.5% of all the

water on earth

• Most of the fresh water is in form of ice in glaciers, ice caps and permafrost.

•

A very very small fraction - about 0.006% of the total water is the freshwater in lakes and

rivers. Most of the remaining freshwater is in groundwater - about 0.75% of the total water

or about 30% of the total freshwater.

• Clean water is vital to our health, communities, and economy.

•

There is no universally accepted deﬁnition of “safe drinking water.” Generally speaking,

safe drinking water, is deﬁned as the water that does not represent any signiﬁcant risk to

health over a lifetime of consumption.

•

Water scarcity can be caused by a mix of hydrological, infrastructural, political and social

issues.

In developing countries, water supply and sanitation related factors cause more than 20

percent of deaths of people under age 14. Nearly half of all people in developing countries

have infections or diseases associated with inadequate water supply and sanitation.

Chemical contaminants in drinking water arise including arsenic, ﬂuoride or nitrate, emerg-

•

Chapter 2. Water Properties and Sources

Figure 2.3: Distribution of Earth’s Water

(From: Igor Shiklomanov’s chapter "Worlds fresh water resources" in Peter H. Gleick (editor),

1993, Water in Crisis: A guide to the world’s Fresh water resources)

2.3 Water Supplies

Atmosphere

Living things

Rivers

Swamps, marshes

Soil moisture

Lakes

3.00%

0.26%

0.49%

2.60%

3.80%

20.90%

Surface water

Ground water

1.20%

Fresh water

2.50%

Ground ice and permafrost 69.00%

30.10%

Glaciers and ice caps 68.70%

Other saline water 0.90%

Oceans 96.50%

Table 2.1: Distribution of Earth’s Water

(From: Igor Shiklomanov’s chapter "Worlds fresh water resources" in Peter H. Gleick (editor),

1993, Water in Crisis: A guide to the world’s Fresh water resources)

ing contaminants such as pharmaceuticals, pesticides, per- and polyﬂuoroalkyl substances

(PFASs) and microplastics generate public concern.

•

Microbiologically contaminated drinking water can transmit diseases such as diarrhoea,

cholera, dysentery, typhoid and polio and is estimated to cause 485 000 diarrhoeal deaths

each year.

The amount of water that is available for sustenance including agriculture, sanitation and

hygiene is limited in many areas of the world. Billions of people throughout the world are

battling daily against enormous difﬁculties accessing the most basic services.

Some 1.1 billion people worldwide lack access to water, and a total of 2.7 billion ﬁnd

water scarce for at least one month of the year.

•

Inadequate sanitation is also a problem for 2.4 billion people—they are exposed to dis-

eases, such as cholera and typhoid fever, and other water-borne illnesses. Two million

people, mostly children, die each year from diarrheal diseases alone.

Many of the water systems that keep ecosystems thriving and feed a growing human pop-

ulation have become stressed. Rivers, lakes and aquifers are drying up or becoming too

polluted to use. More than half the world’s wetlands have disappeared.

Climate change is altering patterns of weather and water around the world, causing short-

ages and droughts in some areas and ﬂoods in others, changing large-scale hydrological

cycle.

•

At the current consumption rate, this situation will only get worse. By 2025, two-thirds of

the world’s population may face water shortages. And ecosystems around the world will

suffer even more

•

Historical rates of progress would need to double for the world to achieve universal cover-

age with basic drinking water services by 2030.

To achieve universal safely managed services, rates would need to quadruple. Climate

change, increasing water scarcity, population growth, demographic changes and urbaniza-

Chapter 2. Water Properties and Sources

tion already pose challenges for water supply systems.

•

Over 2 billion people live in water-stressed countries, which is expected to be exacerbated

in some regions as result of climate change and population growth.

Re-use of wastewater to recover water, nutrients or energy is becoming an important strat-

egy.

Increasingly countries are using wastewater for irrigation; in developing countries this

represents 7% of irrigated land. While this practice if done inappropriately poses health

risks, safe management of wastewater can yield multiple beneﬁts, including increased food

production.

Options for water sources used for drinking-water and irrigation will continue to evolve,

with an increasing reliance on groundwater and alternative sources, including wastewater.

Climate change will lead to greater ﬂuctuations in harvested rainwater. Management of all

water resources will need to be improved to ensure provision and quality.

2.4 Water Sources

Source waters refers to the sources of water - the water bodies or means, which provide

water needed for domestic, agricultural and industrial uses.

•

Figure 2.4: Water Supply Sources

• Water sources include:

1. Surface water (for example, a lake, river, or reservoir)

2.4 Water Sources

2. Groundwater (for example, an aquifer)

3. Recycled water - also called reused water

Figure 2.5: Illustration of Southern California Water Supply Systems

2.4.1 Groundwater

• Groundwater is the water found underground in spaces between sand, rock and soil.

•

Groundwater is stored in aquifers - water-bearing formations underneath the surface that

readily transmit water.

•

Aquifers are underground layers of very porous water-bearing soil or sand with enough

groundwater that it can be pumped to the surface and used for drinking water, irrigation,

industry, or other uses.

•

Water from precipitation, such as rain or snow, naturally ﬁlters through the soil, and is held

within the aquifer.

Groundwater can move through the aquifer and resurface through springs and wells. The

rate at which groundwater moves through an aquifer varies depending on the permeability

of the layer.

• Groundwater is extracted from aquifers via well pumping.

Chapter 2. Water Properties and Sources

Figure 2.6: Los Angeles Area Source Water Summary

•

Groundwater moves from higher elevations to lower elevations and from areas of higher

pressure to areas of lower pressure.

Groundwater is not stored in huge underground caverns, groundwater ﬁlls the pores of

the various kinds of rocks that form the earth below us. Hydrogeology is the study of

groundwater.

•

The presence of the groundwater depends largely on the geology of a speciﬁc area and the

variable porosity of the upper portion of the earth’s crust.

• Access to groundwater is through:

1. Wells - an ordinary well is essentially an a hole in the ground to access the water in

the aquifer.

2. Artesian Well - as the groundwater moves in a aquifer, in certain areas of poor per-

meability, the water is pressurized. In a well dug in this area, the water level will

rise above the top of the aquifer and may even ﬂow onto the land surface - ﬂowing

artesian well

2.4 Water Sources

3. Springs - which is the ﬂow of groundwater onto the earth’s surface through a natu-

ral opening. Springs occur when the contact between an upper aquifer and a lower

aquitard intersects the ground surface

Springs

Groundwater

•

There are two general types of aquifers: conﬁned and unconﬁned. Conﬁned Aquifers

have a layer of impenetrable rock or clay above them, while Unconﬁned Aquifers lie

below a permeable layer of soil.

The layers of earth which hold the groundwater include a spectrum of layer with porous

layer through which the ground water could through easily in the downward direction, at

one end of that spectrum to an Aquiclude which is a geological material through which

zero ﬂow occurs. Then there is the Aquitard in the middle, which is compacted layers of

clay, silt or rock that retards the water ﬂow.

• The replenishment of aquifers by precipitation is called recharging.

•

Aquifers naturally ﬁlter groundwater by forcing it to pass through small pores and between

sediments, which helps to remove substances from the water. This natural ﬁltration pro-

cess, however, may not be enough to remove all of the contaminants. Safe yield is the

maximum quantity of water which can be extracted from an aquifer, yet still maintain the

supply unimpaired.

•

The water table is the surface of the water level in an unconﬁned aquifer at which the

pressure is atmospheric. The water table ﬂuctuates due to recharge or outﬂow from the

aquifer,

•

Perched water table is a small water body separated from the main groundwater by a

relatively small impermeable stratum.

A piezometeric surface or a potentiometric surface is an imaginary surface to which the

water level would rise if a piezometer - an instrument used for measuring the pressure of

groundwater, is inserted in a well drilled in a conﬁned aquifer. A piezometeric surface is

the water table equivalent of a conﬁned aquifer.

• Groundwater can become depleted if used at a faster rate than it can be replenished.

•

Groundwater can become contaminated when an excessive amount of pesticides and herbi-

cides are sprayed on agricultural ﬁelds, septic tanks leak, or landﬁlls are improperly lined

Chapter 2. Water Properties and Sources

or managed and toxic materials seep through the soil into the aquifer.

•

Groundwater can be found at nearly every point in the Earth’s shallow subsurface to some

degree, although aquifers do not necessarily contain fresh water.

Most land areas on Earth have some form of aquifer underlying them, sometimes at sig-

niﬁcant depths. In some cases, these aquifers are rapidly being depleted by the human

population.

•

Many parts of the world are heavily dependent on groundwater due to low levels of rain-

fall.

The United States relies on groundwater for 23 percent of its freshwater needs. In Califor-

nia, that number is signiﬁcantly higher – groundwater provides nearly 40% of the water

used by California’s farms and cities, and signiﬁcantly more in dry years.

Water Wells

Background

•

A well is basically a hole in the ground, held open by a pipe (or casing) that extends to an

aquifer.

• A pump draws water from the aquifer for distribution through the plumbing system.

• Factors dictating the siting of a well include:

– Amount of water needed

– Quality of available water

–

Meet minimum isolation distances required by state rules to ensure safety, and mini-

mize any contamination potential.

• The depth to which wells are constructed is determined by factors including:

1. depth to groundwater

2. groundwater quality, and

3. geological conditions at the well site

Common well terms:

• Static level is the water level in a well when the pump is not operating.

• Pumping level is the water level in the well when it is producing.

•

Drawdown is the difference in elevations between the static level and the pumping level.

The amount of water produced is approximately proportional to the drawdown.

Cone of depression is the depression in the water table formed as the pump draws down the

water level.

Zone of inﬂuence is the area included in the cone of depression. Any contamination in this

zone will be drawn into the well.

Radius of inﬂuence is the farthest distance from the well that the cone of depression affects

the water table.

Speciﬁc capacity is the relationship between the yield of a well and the amount of drawdown

in the well. It can be expressed as a ratio of the yield, in terms of gallons per minute, to the

drawdown in feet. A well producing 100 gpm with a drawdown of 20 feet would have a

2.4 Water Sources

speciﬁc capacity of 5 gpm per foot of drawdown.

•

Recovery time is the amount of time required for the aquifer to stabilize at its static water

level once pumping has stopped.

Figure 2.7: Well terms

Well types

• Wells are classiﬁed by method of construction of the well.

• Well types include:

– Dug wells : These wells are typically:

large diameter

10-30 ft deep

hand-dug to the top layer of the aquifer.

lined with stone or bricks

Dug wells levels ﬂuctuate with seasonal variation of water table and has a high risk

of contamination from nearby land activities.

–

Driven wells: These wells are for reaching shallow waters about 30-50 feet deep

and are made by driving a small diameter pipe. Although the well is cased, it has a

moderate to high evel of risk of contamination from nearby land activities.

Drilled wells: Drilled well is the most common type of well used by public water sys-

tems. These wells are constructed using a rotary-drilling machine and are hundreds

of feet deep. These wells have a continuous casing, which is commonly six-inches

in diameter. These wells are ideally suited to deep water bearing formations where

larger yields are available. This type of well, when properly constructed offers good

protection against contamination from the surface.

Well Construction

Elements of well construction include:

•

Borehole is the narrow shaft drilled to extract water from the aquifer. item Well casing is the

watertight plastic or steel tube lining of the borehole. It is generally 4-6" diameter and it is

primarily to protect the borehole from caving in and to prevent surface water from entering

Chapter 2. Water Properties and Sources

the well. The casing should extend at least 6 to 12 inches above the well pad, depending

on whether the well is located in a well house or out in the open, to prevent standing water

from entering the well.

•

Well screen is installed on the end of a well casing. It supports the bore hole, and it reduces

the amount of sand that enters the casing and the pump.

Gravel packer is a layer of gravel placed around the screen to reduce the amount of ﬁne

material from entering the well through the screen. The gravel packing is usually three

times the diameter of the well screen or a minimum of 4" thick.

•

Grout is cement or bentonite packing around the well casing to protect the well from sur-

face water. The grout is applied continuously from the surface upto the bottom where the

borehole passes into the impermeable layer or upto the gravel packer.

ulGround seal is typically a reinforced concrete slab. This concrete is usually connected to

the grout that extends down the well.

•

Sanitary seal it seals the top of the casing and its primary function is to prevent well con-

tamination. The type of seal varies depending upon the type of pump being used. For a

well using a submersible pump, the sanitary seal is typically composed of a rubber-like

material placed between two pieces of metal. When bolts are tightened on the sanitary seal,

the rubber is compressed and expands to seal against the casing and the pump discharge

pipe.

Figure 2.8: Well construction

2.4.2 Groundwater Under the Direct Inﬂuence of Surface Water

•

Groundwater Under the Direct Inﬂuence of Surface Water (GWUDISW) is the water

which may be subject to contamination with pathogenic organisms from surface waters.

2.4 Water Sources

• GWUDISW is deﬁned as:

Any water beneath the surface of the ground with signiﬁcant occurrence of:

– Insects

– Other macroorganisms

– Algae

– Large diameter pathogens such as Giardia lamblia

or as:

–

Any water beneath the surface of the ground with signiﬁcant and relatively rapid

shifts in water characteristics such as:

Turbidity

Temperature

Conductivity, or

that closely correlates to climatological or surface water conditions.

2.4.3 Surface Water

•

Surface water is water that is open to the atmosphere and results from overland ﬂow. It is

also said to be the result of surface runoff. These are two ways of saying the same thing.

• Examples of surface water include:

– Streams, Rivers, Lakes

– Man-made impoundments - Reservoirs

– Wells drilled next to or in a stream or river

– Rain catchments

•

Surface waters are classiﬁed as either: running waters which include streams, rivers and

brooks; and quiescent waters which include lakes and reservoirs.

A lake is where surface-water runoff (and maybe some groundwater seepage) have accu-

mulated in a low spot, relative to the surrounding countryside. Whereas a reservoir is a

man-made lake that is created when a dam is built on a river.

•

The exposure of surface waters to the atmosphere results in exposure to precipitation

events, surface water runoff and contamination with micro and macroorganisms resulting

from activities in their surrounding areas.

•

Changes in weather cause the natural ﬂow of streams and rivers to vary greatly with time.

Periods of excess ﬂows and valley ﬂooding may alternate with low ﬂows or droughts.

The role of water-storage reservoirs, also known as impoundments is to store water during

periods of higher ﬂows, thus preventing ﬂood disasters, and then permit gradual release of

water during periods of lower ﬂows.

•

Lakes and reservoirs can be classiﬁed into three categories based upon their nutrient con-

tent:

– Eutrophic - rich in nutrient

Chapter 2. Water Properties and Sources

Figure 2.9: Lake/Reservoir Stratiﬁcation

– Mestrophic - moderate amount of nutrient

– Oligotrophic - little or no nutrient

•

In many locations, as the water temperatures decrease with increasing water depth, thermal

stratiﬁcation - formation of distinct thermal layers, of lakes and reservoirs occur due to

temperature related density changes which prevents the vertical mixing of water.

1. Epilimnion - Suface layer of warm, light water (mixed by wind)

2. Thermocline or Metalimnion- Middle layer with rapidly changing temperature

3. Hypolimnion - Lowest layer of coldest and densest water. Hypolimnion usually has

depletion of dissolved oxygen (DO) leading to ﬁsh kills for ﬁsh living at that depth. ·

Destratiﬁcation - can be natural by change in weather or by means such as aeration or

mechanical agitation and mixing.

•

Lake turnover - During autumn and winter, top layer of water gets colder and denser and

sink to the bottom, water from bottom comes to the top causes the bottom sediments to

be stirred causing high turbidity in the water. It can also cause the heav metals (such as

mercury and lead from the bottom of the reservoir become dispersed in the water.

Thus, water intakes are located at various levels in the reservoir to get the best possible

quality of raw intake water possible at different times of the year.

•

2.4.4 Advantages and Disadvantages of Surface Water vs Groundwater

• Advantages of surface water with respect to groundwater:

– It is easily located. It takes no sophisticated equipment to ﬁnd a surface water source.

–

In many parts of the US, considerable data is available on quantity and quality of

existing surface water supplies.

–

Surface water is generally softer than groundwater, which makes treatment much

2.4 Water Sources

simpler.

• Disadvantages of surface water with respect to groundwater:

–

Surface waters can be easily contaminated with microorganisms that cause water-

borne diseases and chemicals that enter the stream from surface runoff and upstream

discharges.

–

The turbidity of a surface water source often ﬂuctuates with the amount of precipita-

tion. Increases in turbidity increase treatment cost and operator time.

The temperature of surface water ﬂuctuates with the ambient temperature. This

makes it difﬁcult to produce consistent water quality at a water treatment plant.

• Advantages of groundwater with respect to surface water:

– Groundwater is not as easily contaminated as surface water.

–

The quality of groundwater, while not always as good as would be preferred, is stable

throughout the year.

–

Groundwater sources are generally lower in bacteriological count than surface water

sources.

– Groundwater is available in most locations throughout the continental US and Alaska.

• Disdvantages of groundwater with respect to surface water:

–

Groundwater usually contains more minerals than surface water, including increased

levels of hardness. Because groundwater is in contact longer with minerals, there is

more time to bring them into solution.

– Removal of groundwater normally requires a pump, thus increasing operation cost.

– Groundwater is more susceptible to long-term contamination from fuel spills.

–

Groundwater supplies often have high levels of iron and manganese, thus increasing

treatment cost and/or causing stains on plumbing and the clothing of customers.

Wells in the coastal areas are subject to salt water intrusion into the aquifer and well.

This contamination is difﬁcult to predict and costly to treat.

Once a groundwater source is contaminated, it is difﬁcult for it to recover. There is

no easy way to remove the contaminants. Sources of contamination can be hidden

from sight.

2.4.5 Recycled Water

•

Water reuse (also commonly known as water recycling or water reclamation) reclaims

water from a variety of sources then treats and reuses it for beneﬁcial purposes such as

agriculture and irrigation, potable water supplies, groundwater replenishment, industrial

processes, and environmental restoration.

•

Water reuse can provide alternatives to existing water supplies and be used to enhance

water security, sustainability, and resilience.

Unplanned or de facto reuse refers to situations in which a source of water is substantially

composed of previously-used water. An example of unplanned water reuse occurs when

communities draw their water supplies from rivers, such as the Colorado River and the

Chapter 2. Water Properties and Sources

Figure 2.10: Sources of Water Contamination

Mississippi River, that receive treated wastewater discharges from communities upstream.

2.5 Water Rights in Claifornia

•

If one takes water from a lake, river, stream, or creek, or from underground supplies for a

beneﬁcial use, California law requires that person to have a water right. The term “beneﬁ-

cial use” can refer to agricultural, mining, urban, industrial, or environmental uses.

In California, water rights law is administered by the State Water Resources Control Board

(often called simply the State Water Board).

•

A water right holder is entitled to a “reasonable” amount of water, which not only consid-

ers the purpose for which the water is being used but also the relative consumption of the

water with regard to other water users in the system.

•

Two types of water are recognized by law in water with regard to the law: groundwater and

surface water.

Groundwater is considered a local supply and there is little state regulation of its use,and

consequently a state water right permit is not required for use of this water.

Primarily, landowners in California are entitled to pump and use a reasonable amount of

groundwater from a basin underlying their land to put it to a beneﬁcial, nonwasteful use.

The use of surface water is subject to state laws and regulations that control its develop-

ment and use.

• Most common surface water rights include:

1. Riparian rights :

–

Riparian rights are rights to the “reasonable and beneﬁcial use of water on land

that is adjacent to a watercourse - a lake, river, stream, or creek.

A riparian right allows the landowner to take as much water as can be reasonably

and beneﬁcially used on the riparian property.

–

2.5 Water Rights in Claifornia

–

Riparian owners must share with other riparian owners along the same water

body, and they cannot waste water or unreasonably affect public trust resources.

2. Appropriative Rights :

–

Appropriative water rights are legal rights to use water from a water source, such

as a river or stream, for beneﬁcial purposes.

Someone who takes water for use on non-riparian land or who uses water that

would not be there under natural conditions on riparian land, appropriates water.

These rights are typically granted based on the principle of "ﬁrst in time, ﬁrst in

right," meaning that the ﬁrst person or entity to beneﬁcially use the water for a

speciﬁc purpose has priority over later users.

–

Appropriative water rights are common in regions where water is scarce and are

often subject to regulations and permitting processes to ensure fair and sustain-

able allocation of water resources.

–

Water right permits and licenses issued by the State Water Board are appropria-

tive water rights.

Appropriative water may be stored for later use, or held for diversion and beneﬁ-

cial use.

3. Prescriptive Rights :

–

A prescriptive right is a right that is acquired through adverse possession of

someone else’s water right. It is similar to a “squatter’s right” to land.

Prescriptive rights originated in the context of conﬂicts between competing

riparian users.

–

Chapter 2 Assessment

1. Groundwaters generally have consistent water quality that include

a. having a higher total dissolved solids content than surface water

b. having a lower mineral content than surface waters

c. having lower pH values than surface waters

d. having a higher amount of bacteria than surface waters

2. When underground water is under pressure greater than atmospheric pressure and could

rise above the its conﬁning space and above the ground level is referred to as a(n)

a. aquifer

b. anaerobic condition

c. artesian effect

d. drawdown

e. pressure gradient

3. The gradual ﬂow or movement of water into and through the pores of the soil is called

a. percolation

b. run-off

c. precipitation

d. impermeable ﬂow

e. evapotranspiration

4. Water that has been used to carry solids away from a home or ofﬁce into a treatment facil-

ity is referred to as

a. wastewater or sewage

Chapter 2. Water Properties and Sources

b. potable

c. seawater intrusion injection water

d. riparian water

5. The water right to put it to beneﬁcial use of the surface water adjacent to your land is

called water.

a. wastewater

b. riparian

c. ﬁlter ripening

d. inﬁltration

e. run-off

6. The difference between static level and pumping level in a well is called:

a. drawdown.

b. cone of depression

c. zone of saturation

d. radius of inﬂuence

7. Which one of the following best deﬁnes the term aquifer?

a. A low lying area where water pools

b. Water-bearing stratum of rock, sand, or gravel

c. Impervious stratum near the ground surface

d. Treated water leaving the water system

8. The height to which water will rise in wells located in an artesian aquifer is called the

a. Pumping water level

b. Water table

c. Piezometric surface

d. Drawdown

e. Radius of inﬂuence

9. To prevent the entry of surface contamination into a well is the purpose of

a. The well casing

b. The water table

c. The louvers or slots

d. Well development

e. The annular grout seal

10. An aquifer that is located underneath an aquiclude is called

a. An unconﬁned aquifer

b. A conﬁned aquifer

c. A water table

d. Unreachable groundwater

e. An Artesian spring

11. The process by which water changes from the gas to the liquid phase is termed

a. Condensation ·

2.5 Water Rights in Claifornia

b. Evaporation

c. Percolation

d. Precipitation

e. Runoff

12. The free surface of the water in an unconﬁned aquifer is known as the

a. Pumping water level

b. Artesian spring

c. Water table

d. Drawdown

e. Percolation

13. The transfer of liquid water from plants and animals on the surface of the earth into water

vapor in the atmosphere is called

a. Transpiration

b. Evaporation

c. Condensation

d. Runoff

e. Percolation

14. The elevation of water in the casing of an operating well is called the

a. Piezometric surface

b. Water table

c. Pumping water level

d. Drawdown

e. Radius of inﬂuence

15. An aquifer under pressure is often termed

a. Unconﬁned

b. Paciﬁc

c. Artesian

d. Alluvial

e. Elevated

16. An aquifer is usually composed of

a. Sand and gravel

b. Clays and silts

c. Bedrock

d. Large voids in the soil, resembling underground lakes

e. None of the above

17. Which of the following best deﬁnes the term speciﬁc capacity?

a. Amount of water a given volume of saturated rock or sediment will yield to gravity

b. Amount of water a given volume of saturated rock or sediment will yield to pumping

c. Rate at which water would ﬂow in an aquifer if the aquifer were an open conduit

d. Amount of water a well will produce for each foot of drawdown

Chapter 2. Water Properties and Sources

18. The most common type of well used for public water supply systems is a

a. Jetted well

b. Driven well

c. Drilled well

d. Bored well

19. An aquifer that is underneath a layer of low permeability is known as

a. Conﬁned aquifer

b. Water Table aquifer

c. Unconﬁned aquifer

d. Unreachable groundwater

20. What is the middle layer of a stratiﬁed lake known as?

a. Hypolimnion

b. Benthic Zone

c. Thermocline

d. Epilimnion

21. The amount of water that can be pulled from a aquifer without depleting

a. Drawdown

b. Safe yield

c. Overdraft

d. Subsidence

Chapter 3

III

Water Quality & Laboratory Procedures 53

Organics

3.1

3.2

3.3

3.4

3.5

3.6

Inorganics

Radionuclides

Microbial contaminants

Water quality tests

Sampling

3. Water Quality & Laboratory Procedures

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams

Ability to read a graduated cylinder

Ability to interpret coliform test results

Knowledge of coliform analysis methods

Knowledge of coliform bacteria types

Knowledge of the deﬁnition of pathogenic organisms

Knowledge of holding times (e.g. preservatives)

Knowledge of water sampling techniques for bacteriological, organic, and inorganic constituents

Knowledge of the use of coliform as a surrogate

Ability to distinguish between presumptive and conﬁrmed results

Knowledge of nitrate formation in a distribution system

Knowledge of potential waterborne diseases

Knowledge of the effects of abnormal pH levels in a distribution system

Knowledge of the effects of hardness in a distribution system

Knowledge of the effects of heterotrophic bacteria in a distribution system

Knowledge of the galvanic series

Knowledge of the Langelier Index

Knowledge of common inorganic contaminant compounds pH, Conductivity, Hardness, and

Turbidity

Knowledge of common organic contaminant compounds

Knowledge of sources of inorganic contaminants in a distribution system

Knowledge of sources of organic contaminants in a distribution system

Ability to interpret a Langelier Index

Chapter 3. Water Quality & Laboratory Procedures

Expected Range of Knowledge for Water Properties and Sources

Water Treatment Operator License Exams

Ability to recognize abnormal chemical characteristics of water

Ability to recognize abnormal odors or colors

Knowledge of chemicals that contribute alkalinity and hardness to water

Knowledge of common chemical and microbial contaminants in raw water

Knowledge of problems caused by hard water

Knowledge of the chemical components of groundwater and surface water

Ability to interpret turbidity information

Knowledge of turbidity causing matter

Knowledge of chemicals that contribute hardness to water

Ability to recognize corrosion problems

Knowledge of pH adjustment procedures

Knowledge of corrosion causes

Knowledge of abnormal taste and odors

Knowledge of chemicals that contribute taste and odor

Knowledge of taste and odor treatment processes

Ability to recognize an iron and manganese problem

Knowledge of health effects of lead and copper

Knowledge of adverse health effects caused by common contaminants

Ability to collect a water sample

Ability to determine a proper sampling site

Ability to follow chain of custody

Knowledge of appropriate sample containers and sample sizes

Knowledge of maximum holding times

Knowledge of proper sampling and preservation techniques

Knowledge of well sampling techniques

Knowledge of chemical hazards

Ability to analyze a water sample for free and total chlorine

Ability to read and interpret a colorimeter

Knowledge of approved analytical procedures for chlorine analysis

Ability to read and interpret a pH meter

Knowledge of acids and bases

Knowledge of acceptable water pH range

Knowledge of chemicals that affect the pH of water

Knowledge of the effects of pH on water quality

Knowledge of the pH scale

Ability to analyze a water sample for pH

Ability to analyze a water sample for turbidity

Ability to read and interpret a turbidimeter

Knowledge of the Nephelometric Turbidity Unit (NTU) scale

Knowledge of turbidimeter instrumentation

Knowledge of turbidity level requirements

Ability to identify an objectionable taste or odor in water

Knowledge of chemicals that contribute taste and odor to water

Knowledge of the presence/absence test method

Knowledge of approved analytical procedures for coliform analysis

Knowledge of common microbial contaminants in raw water

Ability to interpret water quality characteristics (hardness, turbidity, pH )

Expected Range of Knowledge for Water Properties and Sources

Water Treatment System Operator License Exams (Continued)

Ability to recognize abnormal chemical characteristics of water

Ability to prepare and calibrate turbidimeter with Primary Standard (Formazin)

Ability to analyze a water sample for water hardness

Ability to recognize abnormal colors in water

Knowledge of Heterotrophic Plate Count (HPC)

Knowledge of the Langelier Index

Knowledge of corrosion control chemical reactions

Knowledge of iron and manganese oxidation chemistry

Knowledge of chemicals that contribute alkalinity to water

Ability to use a titrator

Ability to recognize a titration endpoint

Knowledge of abnormal alkalinity levels

Ability to analyze a water sample for speciﬁc conductance

Ability to read and interpret a speciﬁc conductance meter

Knowledge of abnormal color levels

Ability to distinguish between presumptive and conﬁrmed coliform results

Knowledge of the multiple tube fermentation method

Knowledge of the membrane ﬁltration method

Knowledge of the health effects of ﬂuoride

Ability to calculate a TDS value from a speciﬁc conductance reading

Knowledge of EC/TDS ratio

Ability to calibrate a speciﬁc conductance meter

Ability to operate an Ion Speciﬁc Electrode (ISE)

Knowledge of optimal ﬂuoride level range

Knowledge of color analysis scale

Knowledge of true and apparent color

Knowledge of odor analysis protocol

Chapter 3. Water Quality & Laboratory Procedures

Water occurring in nature will have other elements dissolved or suspended in it. A "contaminant"

is a physical, chemical, biological, or radiological substance or matter, in water. The type and

amount of these contaminants will affect the property and safety of that water, if it is to be used

as drinking water. Some drinking water contaminants may be harmful if consumed at certain

levels in drinking water while others may be harmless. The presence of contaminants does not

necessarily indicate that the water poses a health risk.

Contaminants in drinking water can be broadly categorized as:

•

Chemical contaminants which may be naturally occurring or man-made elements or com-

pounds. Examples of chemical contaminants include nitrogen, bleach, salts, pesticides,

metals, and human or animal drugs.

•

Biological contaminants which are also refered as micorbes or microbiological contaminants

which include bacteria, viruses, protozoa and parasites. organisms

Radiological contaminants which are chemical compounds or elements which contain

unstable atoms that emit ionizing radiation. Example of radiological contaminants include,

cesium, plutonium and uranium.

3.1 Organics

• Organics – are carbon based material can originate from lifeforms or can be man-made.

• Only few carbon compounds such as carbonates, cyanides are not classiﬁed as organic.

• In water they originate from decaying plant and animal life and wastes.

• Amount present in natural waters is usually low.

•

Many organic compounds are soluble in water, and surface waters are more prone to con-

tamination by natural organic compounds than are groundwaters.

•

Synthetic organic compounds, such as polychlorinated biphenyls (PCBs), dioxin, and

dichlorodiphenyl-trichloroethane (DDT), all of which are toxic, often persist and accumu-

late because they do not readily break down in natural ecosystems.

Many of the organic compounds found in water are known to cause cancer and birth de-

fects in people.

•

• Organic matter in water is responsible for:

– Color formation

– Taste and odor problems

– Oxygen depletion in streams

– Interference with water treatment processes, and

– Formation of halogenated compounds when chlorine is added to disinfect water.

•

The quantity of oxygen-consuming organics in water is usually determined by measuring

its biochemical oxygen demand( BOD )

BOD is the amount of dissolved oxygen required by aerobic decomposers to break down

the organic materials in a given volume of water over a 5-day incubation period at 20 Deg.

C (68 Deg. F).

3.2 Inorganics

do not contain carbon and are not derived from living material. The inorganics include metals,

acids, bases, salts, oxides, sulfate, phosphates, etc.

3.2.1 Metals

• Iron and Magnesium:

–

Although iron and manganese are most commonly found metals in groundwaters,

surfacewaters may also contain signiﬁcant amounts at times.

Non-pathogenic bacteria feed on iron and manganese in water to form red-brown

(iron) or black-brown (manganese) slime which accumulates on spouts and inside

toilet tanks.

–

Iron is a secondary or aesthetic contaminant and dissolved iron gives water a disgree-

able metallic taste.

An iron concentration of 0.3 mg/l can cause water to turn a reddish brown color and

leave reddish brown stains which are very hard to remove.

• Calcium and magnesium:

–

The metals most often found in the highest concentrations in natural waters are cal-

cium and magnesium. These are usually associated with a carbonate anion and come

from the dissolution of limestone rock.

–

Calcium and magnesium are nontoxic and normally absorbed by living organisms

more readily than the other metals; therefore, if the water is hard, the toxicity of a

given concentration of a toxic metal is reduced.

–

Conversely, in soft, acidic water, the same concentrations of metals may be more

toxic.

In natural water systems, other nontoxic metals are generally found in very small

quantities. Most of these will cause taste problems well before they reach toxic lev-

els.

• Heavy metals:

Even in small quantities, toxic metals including: arsenic, barium, cadmium,chromium,

–

lead, mercury, and silver in drinking water are harmful to humans and other organ-

isms. Arsenic, cadmium, lead and mercury, all cumulative toxins, are particularly

hazardous.These particular metals are concentrated by the food chain, thereby posing

the greatest danger to organisms near the top of the chain.

3.2.2 Salts

•

A salt is formed when a metal ion (cation - because it has a positive charge) combines with

a nonmetal ion (anion - - because it has a negative charge). For instance, when a metal like

sodium combines with a non-metal ion like chloride to form sodium chloride, NaCl, or

table salt.

Chapter 3. Water Quality & Laboratory Procedures

Figure 3.1: Metals in Drinking Water - Health Hazards

•

Common metal anions and cations that combine to form salts which are commonly found

in drinking water supplies or used in Water treatment are listed in the table below.

METAL ION (CATION)

NON-METAL ION (ANION)

−1

Calcium - Ca⁺²

Magnesium - Mg⁺²

Manganese - Mn⁺²

Iron - Fe^+2/+3

Carbonate - CO₃

−1

Bicarbonate - HCO₃

Hydroxide - OH⁻¹

−2

Sulfate - SO₄

Chloride - Cl⁻¹

Aluminum - Al⁺³

Sodium - Na⁺¹

Copper - Cu^+2/+3

Table 3.1: Salts constituents

3.2.3 Nutrients

•

Plant nutrients - nitrogen and phosphorous, present in water promote growth of plant and

algal matter in the receiving waters causing destruction of the normal aquatic life mainly

due to oxygen depletion - eutrophication.

•

Major sources of nitrogen include runoff from animal feedlots, fertilizer runoff from agri-

cultural lands, municipal wastewater discharges, and certain bacteria and blue-green algae

than can obtain nitrogen directly from the atmosphere In addition,certain forms of acid

rain can also contribute nitrogen to surface waters. Nitrogen in water is commonly found

in the form of nitrate (NO₃)

•

Nitrate in drinking water can lead to serious problems, speciﬁcally nitrate poisoning which

can lead to death. Bacteria commonly found in the intestinal tract of infants can convert

nitrate to highly toxic nitrites (NO₂). Nitrite can replace oxygen in the bloodstream and

result in oxygen starvation, which causes a bluish discoloration of the infant known as

3.2 Inorganics

CHEMICAL NAME

FORMULA

Al₂(SO₄)₃

COMMON NAME

Alum

Aluminum sulfate

Calcium oxide

CaO

Quicklime

Calcium hydroxide

Calcium carbonate

Calcium hydroxide

Magnesium carbonate

Magnesium bicarbonate

Sodium hydroxide

Sodium carbonate

Ferrous sulfate

Ca(OH)₂

CaCO₃

Ca(OH)₂

Mg(CO₃)₂

Mg(HCO₃)₂

NaOH

Slaked/hydrated lime

Limestone

Slaked/hydrated lime

Caustic soda

Soda ash

Copperas

Na₂CO₃

FeSO₄

Ferric chloride

FeCl₃

Ferrous chloride

Copper sulfate

FeCl₂

CuSO₄

Table 3.2: Salts found in water and/or used in water treatment

Infant Methemoglobinemia or blue-baby syndrome .

•

Major sources of phosphorous include phosphates in detergents, fertilizers and feedlot

runoff, as well as municipal wastewater discharges.

Phosphate is added as part of the water treatment for corrosion control and for improving

taste and odor by sequestering iron and magnesium.

3.2.4 Trace Constituents

• Trace Constituents are chemicals found in extremely low concentrations.

• Trace constituents include:

– B - Boron

– Miscellaneous metals

– Hormones

–

EDCs - Endocrine-disrupting compounds are synthetic and natural compounds that

mimic, block, stimulate, or inhibit natural hormones in the endocrine systems of

animals, including humans. The origins include pesticides, pharmceutically active

chemicals (PhACs), personal care products (PCPs), herbicides, industrial chemicals,

and disinfection byproducts (DBPs).

–

PCPs - Personal Care Products are products such as shampoo, hair conditioner, de-

odorants, and body lotion.

– Pharmaceuticals - aspirin, ibuprofen, caffeine, etc.

–

CECs - Constituents of Emerging Concern is a general term applied to constituents

that have relatively recently become known as a potential concern and likely have

little to no information available to fully comprehend and establish safe and realistic

standards, such as PFAS/PFOA.

Chapter 3. Water Quality & Laboratory Procedures

3.3 Radionuclides

•

Radioactive materials, also called radionuclides, are both naturally occurring and human-

made.

•

Radionuclides such as radium, radon and uranium can get into groundwater and surface

waters from natural sources and also potentially from human sources such as active nuclear

power plants or other facilities that make or use radioactive substances.

When radionuclides break down (decay), they emit radioactive particles such as alpha-

particles, beta-particles and gamma-rays radiation which could present a risk to human

health.

•

Most water systems have no detectable radionuclide activities, some areas of the United

States have signiﬁcantly higher levels than the national averages.

People who are exposed to relatively high levels of radionuclides in drinking water for

long periods may develop serious health problems, such as cancer, anemia, osteoporosis,

cataracts, bone growths, kidney disease, liver disease and impaired immune systems.

The health risks associated with radionuclides are normally small compared with the risks

from microorganisms and chemicals that may be present in drinking-water.

The amount of radionuclides in drinking water is quantiﬁed and regulated under the EPA’s

Radionuclide Rule, by standards based upon both, the radioactivity levels as measured by

the radiation of alpha and beta particles and the amount of commonly found radioactive

elements - radium and uranium, quantiﬁed in terms of their radioactivity.

•

• For drinking water, radiation/radioactivity levels is measured as pCi/L (picocuries per liter)

3.4 Microbial contaminants

Many types of pathogenic - disease-causing germs can be found in contaminated drinking

water, including bacteria, viruses and parasites.

•

• Common virus in drinking water source and their associated diseases include:

– Adenoviruses - tonsillitis, conjunctivitis, the common cold and other illnesses.

– Reoviruses - colds, ﬂu, diarrhea, chicken pox, measles and mumps.

– polioviruses - polio

– hepatitis A virus

• Some of the water borne pathogenic bacteria and their associated disease include:

– Salmonella typhi - Typhoid fever

– Vibrio cholerae - cholera

– Yersinia enterocolitica - gastroenteritis

• Common intestinal parasites and their associated disease include :

– Entamoeba histolytica - Amoebic Dysentery.

– Giardial lamblia (Giardiasis) .

– Ascaris lumbricoides (Giant Roundworm).

– Cryptosporidium (Cryptosporidiosis) .

3.5 Water quality tests

•

The aesthetic quality aspects of drinking water include: taste, odor, color, turbidity, hard-

ness, and temperature.

The aesthetics are generally not health-related. However, consumers can easily detect

them, so they can have signiﬁcant effects on perceptions of water quality and acceptability.

These attributes are the source of most complaints to water suppliers and frequently lead

consumers to choose home treatment or bottled water.

3.5.1 Turbidity

• Measures cloudiness of water due to suspended particles.

•

Higher turbidity levels are often associated with higher levels of disease-causing microor-

ganisms.

• Turbidity affects both the acceptability of water to consumers

•

Harmful pollutants such as heavy metals and pesticides are easily absorbed by suspended

solids

•

Turbidity affects disinfection as suspended particles in water act as a protective shield for

micro-organisms and provide an excellent substrate for bacteria growth. Higher disinfec-

tion doses or contact times are required to ensure adequate treatment.

Suspended solids represent a risk for the main water distribution systems, pumps and other

equipment where tend to deposit and block pipes and nozzles.

•

Turbidity is an optical measurement of water’s ability to scatter and absorb light rather

than transmit it in straight lines. It is commonly measured in the unit of Nephelometric

Turbidity Units (NTU).

•

"Crystal-clear” water has a turbidity of <1 NTU; at 4 NTU and above, water becomes

visibly cloudy at 25 NTU it is murky.

• An average person is able to see turbidity with the naked eye at NTU level of 5 and above.

• Sources of turbidity:

1. In source water, turbidity can be attributed to:

– Inorganic particles released by weathering of rocks, soils and clays

– Human, livestock and industrial wastes

– Biological growth (e.g. algae, zooplankton and cyanobacteria) in source waters

– Natural organic matter including decomposing plant material

2. Introduction of turbidity during treatment can be due to:

–

Poor control of treatment chemical dosing (e.g. coagulants, settling aids and pH

adjustment chemicals)

–

Precipitates from insoluble components of treatment chemicals, or formed dur-

ing processes such as pH correction

– Oxidation products of natural chemicals such as arsenic, iron and manganese

3. Turbidity can also be introduced in the distribution system by:

Chapter 3. Water Quality & Laboratory Procedures

– Intrusion of soils and sewage through mains breaks

– External contamination from backﬂow or cross connections

–

Resuspension of accumulated silts and sediments, or detachment of corrosion

chemicals and scales and detachment of bioﬁlms

• Formazin - a chemical, is used for preparing solutions of known turbidities.

3.5.2 Color

•

Color may affect the turbidity value but is distinct from turbidity as color is due to or-

ganic material that has dissolved into solution, while turbidity consists of tiny particles

suspended in the water column.

3.5.3 Taste and odor

Odor and taste are useful indicators of water quality even though odor and taste-free water

is not necessarily safe to drink nor water with some odors or taste is necessarily harmful.

• Taste and odors are often grouped with odor because of their common origin factors.

•

The cause of taste and odor issues can be from water ﬁxtures, plumbing materials, water

heaters, water treatment, pressure tanks and/or the source (the well).

Taste and odors are generally attributed to the presence of organic and some inorganic

chemicals which come from the decaying organic matter, runoffs, industrial wastes, and

municipal sewage discharges.

•

Geosmin and methyl-isoborneol (MIB) are often the cause of earthy-musty odors occuring

in fall due to the turnover of lakes and reservoirs. They are produced by bacteria, particu-

larly actinomycetes and cause odor issues at a very low concentrations.

In the groundwater, the tastes and odors can be due to iron, manganese, and hydrogen

sulﬁde (H₂S).

•

Often, identifying the exact origin of taste and odor is usually very expensive and often

impossible, and removal of the causative substance is even harder.

Current methods of measuring taste and odor are still fairly subjective. Standards related to

odor and taste: Chloride, Copper, Foaming Agents, Iron, Manganese pH, Sulfate, Thresh-

old Odor Number (TON) which is the greatest dilution of a sample with odor-free water

that still yields a just-detectable odor.

3.5.4 Temperature

•

Temperature affects the solubility of oxygen in water, the rate of bacterial activity, and the

rate at which gases are transferred to and from the water.

•

Cool water is generally more palatable than warm water, and temperature will have an

impact on the acceptability of a number of other inorganic constituents and chemical

contaminants that may affect taste.

•

High water temperature enhances the growth of microorganisms and may increase prob-

lems related to taste, odour, colour and corrosion.

3.5 Water quality tests

•

Water temperature determines, in part, how efﬁciently certain water treatment processes

operate. For example, temperature has an effect on the rate at which chemicals dissolve

and react. When water is cold, more chemicals are required for efﬁcient coagulation and

ﬂocculation to take place. When water temperature is high, the result may be a higher

chlorine demand because of the increased reactivity, as well as an increased level of algae

and other organic matter in raw water.

•

Heat is added to surface and groundwater from natural and man-made sources. Surface

waters in particular are potentially subject to great temperature variations.

Other sources of increased temperatures in running water result from forest clearing and

return of irrigation ﬂows to a body of running water.

3.5.5 Total dissolved solids

Total dissolved solids (TDS) is a part of total solids (TS) in water and are the material

remaining in water after ﬁltration.

•

• Components of water TDS include:

– Minerals from rocks and soil as water passes over and through them.

– Pesticides and herbicides from agricultural runoff

– Lead and copper from plumbing pipes

– Chemicals added during water treatment

– Human and animal wastes

– Biological decay products

•

Water has an equilibrium state with respect to dissolved portion; thus, if water is under

saturated, it will aggressively dissolve materials it comes into contact with. Because of

this problem, certain soluble substances, typically calcium and magnesium based sub-

stances are added post water treatment to minimize its corrosivity effects in the distribution

system.

Dissolved solids can be removed from water by distillation, electro-dialysis, reverse osmo-

sis, or ion exchange.

• TDS is measured in mg/L or ppm.

•

As water will conduct electricity due to the presence of dissolved inorganic ions, higher

the concentration of these ions, the higher is the conductivity. Thus, speciﬁc conductance -

conductivity measurement, provides a good estimate of the water’s TDS.

The terms “speciﬁc conductance,” “speciﬁc electrical conductance,” and “electrical con-

ductivity” are used interchangeably and its unit of measurement is in siemens per centime-

ter (S/cm) or mhos per centimeter (mhos/cm).

•

The TDS concentration is considered a Secondary Drinking Water Standard, which means

that it is not a health hazard.

EPA has established a Secondary Drinking Water Standard of a maximum concentration of

500 mg/l of TDS in drinking water and recommends treatment when TDS concentrations

exceed 500 mg/L, or 500 parts per million (ppm).

Chapter 3. Water Quality & Laboratory Procedures

3.5.6 Alkalinity

•

Alkalinity is a measure of the ability of water to neutralize acid, or an expression of its

buffering capacity.

• Constituents of alkalinity are: Bicarbonate – HCO₃, Carbonate - CO₃, Hydroxide - OH⁻

• Measured in equivalent of mg/L CaCO₃

• Alkalinity levels can be classiﬁed as:

– Low Alkalinity - < 20 mg CaCO₃/L

– Moderate Alkalinity - 20 to 160 mg CaCO₃/L

– High Alkalinity - > 160 mg CaCO₃/L

• High alkalinity indicates the scaling (deposit forming) potential and salty taste

•

Low alkalinity implies undersaturation of water (absence of dissolved content) and thus

would exhibit higher corrosion potential - tendency to dissolve metals.

• Alkalinity originates naturally as water moves through rocks dissolving minerals.

•

Alkalinity is important for ﬁsh and aquatic life because it protects or buffers against rapid

pH changes. In addition, alkalinity levels affect the efﬁciency of certain water treatment

processes, especially the coagulation process.

3.5.7 Hardness

•

Hardness is due to the presence of multivalent metal ions, which come from minerals

dissolved in water. The dissolution of these minerals is aided by the carbonic acid formed

by the dissolution of naturally occuring carbon dioxide in water.

Domestic use of hard water is marked by lack of foam formation with soap solutions

due to the formation of a white precipitate (soap scum) instead of producing lather and

noticeable limescale in kettles and water heaters.

Calcium (Ca) and Magnesium (Mg) are the two metals that dissolve the most easily in

water. They are considered to be the main cause of hardness.

• Hardness causing compounds are broken into two groups:

–

Carbonate hardness or temporary hardness which is the hardness that can be removed

by boiling water.

Carbonate hardness is formed when calcium or magnesium combines with a

form of alkalinity (carbonate, bicarbonates, or hydroxides.)

– Non-carbonate hardness cannot be removed by boiling water.

Non-carbonate hardness is formed when calcium and magnesium combine with

anything other than alkalinity. Chlorides and sulfates are the two most common

forms of non-carbonate hardness.

•

Hard water when used in industrial applications forms deposits - scale composed mainly

of calcium carbonate (CaCO₃), magnesium hydroxide (Mg(OH)₂), and calcium sulfate

(CaSO₄)on the inside surfaces of pipes and heat exchangers. The scale formed restricts the

ﬂow of water, heat transfer causing metal boiler components to overheat.

3.5 Water quality tests

• Water hardness has not be found to cause adverse health effects in humans.

•

Generally speaking, groundwaters are harder than surface waters. In freshwater, the pri-

mary ions are calcium and magnesium; however, iron and manganese may also contribute.

Hardness is classiﬁed as carbonate hardness or non carbonate hardness. Carbonate hard-

ness is equal to alkalinity but a non-carbonate fraction may include nitrates and chlorides.

Hardness values are expressed as an equivalent amount or equivalent weight of calcium

carbonate.

Water with a hardness of less than 50 ppm is soft. Above 200 ppm, domestic supplies are

usually blended to reduce the hardness value.

The grain per gallon is a unit of water hardness deﬁned as 1 grain (64.8 milligrams) of

calcium carbonate dissolved in 1 gallon of water. It translates into 17.1 parts per million

(ppm).

•

Hardness of water is determined by titrating with a standard solution of ethylene diamine

tetra acetic acid (EDTA) which is a complexing agent .

Note: Alkalinity and hardness can be seen as two sides of the same coin. Typical minerals found

in water include - CaCO₃, Ca(HCO₃)₂, CaSO₄, MgCO₃, Mg(HCO₃)₂- the cations of these min-

erals - Ca⁺²and Mg⁺²contribute to hardness while the anions - CO⁻₃²,SO₄⁻²HCO⁻₃contribute

to the alkalinity. These dissolved minerals are measured as part of the TDS. Thus, in natural

waters - TDS, alkalinity and hardness are typically correlated.

3.5.8 pH

pH is a measure of the hydrogen ion (H⁺) content or the acidity or basicity of a solution. pH

impacts the chemical and microbiological elements of water treatment processes and thus pH

measurement and control is critical.

• Pure water dissociates into equal concentration of hydrogen ions and hydroxide ions:

H₂O → H⁺+OH⁻.

• The H⁺are responsible for acidic properties and the OH⁻ions for the basic properties.

•

pH is the inverse of H⁺concentration; pH increases when the concentration of H⁺de-

creases relative to the concentration of OH-.

pH scale ranges from 0 – 14. When the concentration of both H⁺and OH⁻are equal, as in

pure water, it is considered neutral and its pH is 7.0.

If the pH of a sample solution is below 7.0, the sample is termed acidic and is alkaline or

basic if its pH is above 7.0.

Each change of 1 pH unit represents a 10 fold change in concentration. For example, a

sample with a pH of 2.0 is 1000 times more acidic than a sample with a pH of 5.0.

• The affects of drinking water pH include:

– Taste and odor impacts.

–

Solubility and biological availability of chemical constituents such as nutrients -

phosphorus, nitrogen, and carbon.

–

Solubility and toxicity of heavy metals. Metals tend to be more toxic at lower pH

Chapter 3. Water Quality & Laboratory Procedures

because they are more soluble.

•

pH is measured by an electrode that is sensitive only to H⁺or using a pH strip which is

essentially an adsorbent paper which is pre-impregnated with chemicals which change

color under different H⁺concentrations.

It is important to measure pH at the same time as chlorine residual since the efﬁcacy of

disinfection with chlorine is highly pH-dependent; where the pH exceeds 8.0, disinfection

is less effective. To check that the pH is in the optimal range for disinfection with chlorine

(less than 8.0), simple tests may be conducted in the ﬁeld using comparators such as that

used for chlorine residual. With some chlorine comparators, it is possible to measure pH

and chlorine residual simultaneously.

•

Alternatively, portable pH electrodes and meters are available. If these are used in the

laboratory, they must be calibrated against fresh pH standards at least daily; for ﬁeld use,

they should be calibrated immediately before each test. Results may be inaccurate if the

water has a low buffering capacity.

3.5.9 Langelier Index

•

The Langelier Index is an approximate indicator of the degree of saturation of calcium

carbonate in water.

It is calculated using the pH, alkalinity, calcium concentration, total dissolved solids, and

water temperature of a water sample collected at the tap.

The sign and magnitude of the Langelier index show the water’s tendency to form or dis-

solve scale and thus to inhibit or encourage corrosion:

–

A negative Langelier Index indicates calcium carbonate under-saturation and water

will have a higher corrosion potential.

Positive Langelier Index indicates calcium carbonate over-saturation and indicates

scaling potential of that water.

Water with a Langelier Index of close to zero, indicates water which is not corrosive

nor scale forming.

• Langelier index can be utilized to identify the water supply systems’ leakage potential.

3.5.10 Chlorine Residual

• Chlorine in one form or another is the principal disinfecting agent employed.

•

An important additional advantage over some other disinfectants is that chlorine leaves a

disinfectant residual that assists in preventing recontamination during distribution, trans-

port, and household storage of water.

•

The absence of a chlorine residual in the distribution system may, in certain circumstances,

indicate the possibility of post-treatment contamination.

• Three types of chlorine residual may be measured:

1. Free chlorine - the most reactive form, which is the chlorine present as hypochlorite

(OCl⁻), hypochlorous (HOCl) or a combination of the two.

3.5 Water quality tests

2. Combined chlorine - the less reactive but more persistent form, consisting of chlo-

rine that is combined with ammonia, nitrogen, or nitrogenous compounds (chlo-

ramines). This is the amount of chlorine that has reacted with nitrates and is unavail-

able for disinfection.

3. Total chlorine - which is the sum of the free and combined chlorine residuals.

Free chlorine is unstable in aqueous solution, and the chlorine content of water samples

may decrease rapidly, particularly at warm temperatures. Also, exposure to strong light

or agitation will accelerate the rate of loss of free chlorine. Water samples should be

analyzed for free chlorine immediately on sampling and not stored for later testing.

DPD - N,N-diethyl-p-phenylenediamine , is a commonly used method of measuring the

chlorine residual in water. DPD reacts directly with disinfectants (e.g. chlorine, chlo-

ramines etc.) to produce a pink colored solution. The intensity of this colored solution is

proportional to the concentration of disinfectant in the sample.

•

Residual chlorine analysis of a water sample is preferably to be conducted immediately,

but must be done within 15 minutes of sampling.

• Amperometric sensors are also used for chlorine measurements.

• Advantages of amperometric method include:

– Chemical reagents are not required

–

Sensors are relatively free from interference from color, turbidity, and interference

from iron, manganese, nitrate and chromates present in the sample.

3.5.11 Density

•

Density is deﬁned as the weight of a substance per a unit of its volume. For example,

pounds per cubic foot or pounds per gallon.

• Here are a few key facts about density:

–

Density is measured in units of lb/ft3, lb/gal, or mg/L. Density of water = 62.4 lb/ft3

= 8.34 lb/gal.

– Density of concrete = 130 lb/ft3. Density of alum (liquid @ 60°F) = 1.33

– Density of hydrogen peroxide (35

3.5.12 Speciﬁc Gravity

•

Speciﬁc gravity is a relationship of the liquid to water. A liquid that is heavier than water

will have a speciﬁc gravity greater than one. If you know the weight per gallon of the

liquid you can ﬁnd the speciﬁc gravity of the material by dividing the weight per gallon by

the weight of one gallon of water.

• Here are a few key facts about speciﬁc gravity:

–

Speciﬁc gravity has no units. Speciﬁc gravity of water = 1.0 Speciﬁc gravity of con-

crete = 2.08

–

Speciﬁc gravity of alum (liquid @ 60°F) = 1.33 Speciﬁc gravity of hydrogen perox-

ide (35

Chapter 3. Water Quality & Laboratory Procedures

•

Any substance with a density greater than that of water will have a speciﬁc gravity greater

than 1.0. Any substance with a density less than that of water will have a speciﬁc gravity

less than 1.0. The density and speciﬁc gravity of a substance indicates whether it will sink

or ﬂoat in water. If its density is greater than that of water (1.0), it will sink; if less, it will

ﬂoat.

Example Problem: A liquid chemical is determined to weigh 9.17 lb/gal. What is the speciﬁc

gravity of the chemical? Also, specify if the chemical will sink or ﬂoat in the water?

Speciﬁc Weight of Substance, lb/gal 9.17

Speciﬁc Gravity =

= 1.1

Weight of Water, lb/gal

8.34

This chemical will sink when added to water (if insoluble or until it is solubilized) because it is is

denser than water - its speciﬁc gravity is 1.1.

3.5.13 Microbial testing

•

It is not practical to monitor for every pathogen that may potentially be present in drinking

water source, thus an “indicator organism approach” to assess the microbiological quality

of drinking water is adopted.

•

“Coliform” bacteria-particularly Escherichia coli (better known as E. coli) are used as the

indicator organims.

These coliform bacteria originate from feces and indicate fecal contamination and thus

serve as an indicator organisms for pathogens of wastewater origin

• They are also:

– abundant

– potentially less harmful, and

– easy to detect

•

The methods for water bacteriological tests include: multiple-tube fermentation (MTF)

technique, membrane ﬁltration (MF), Presence - Absence Method, and quanti-tray testing.

When using the MTF and MF methods, it is not possible to exactly quantify the number of

bacteria present, a statistical based - Most Probable Number (MPN) approach is utilized

The Multiple-Tube Fermentation technique

Stage 1. Presumptive Test:

Step 1. Multiple-Tube Fermentation (MTF) technique involves adding three volumes – 10

ml, 1 ml and 0.1 ml of the sample, each to a set of ﬁve tubes containing Lauryl Tryp-

tose broth and an inverted tube (Durham tube),

Step 2. The tubes are incubated for 24 hours and after incubation the tubes are checked for

positive results. The Lauryl Tryptose broth produces color and/or turbidity change

due to the growth of the target bacteria and the inverted tube collects the gas pro-

duced by the bacterial respiration.

Stbge 2. Conﬁrmed Test:

Step 1. Each positive is innoculated into bacteria speciﬁc broth and observed for positive

3.5 Water quality tests

results after incubating the innoculated samples for 24 hours.

Step 2. The number of tubes showing bacterial growth are counted for each volume of sam-

ple and using this information the concentrations of organisms in the original sample

are established using Statistical Tables.

Stcge 3. Completed Test:

Step 1. An innoculum from the Conﬁrmed positive is streaked on agar plates and incubated

Step 2. The colonies from the agar plate are innoculated on an agar slant and nutrient broth

and incubated.

Step 3. The above incubated samples are observed for positive results.

Figure 3.2: Multiple Tube Fermentation

Chapter 3. Water Quality & Laboratory Procedures

Membrane Filtration Method Membrane ﬁltration (MF) is a faster way to estimate bacterial

populations in water. In this method, an appropriate sample volume is passed through a mem-

brane ﬁlter with a pore size small enough (0.45 micron) to retain the bacteria present. The ﬁlter

is placed on an absorbent pad (in a petri dish) saturated with a culture medium that is selective

for coliform growth. The petri dish containing the ﬁlter and pad is incubated, upside down, for

24 hours at the appropriate temperature. After incubation, the colonies that have grown are iden-

tiﬁed and counted using a low power microscope. A MUG medium is used for E- Coli. If E. Coli

is present, it will make the MUG ﬂuorescent when viewed in UV light.

3.5 Water quality tests

Quanti-trays tests

This test used for the detection and quantiﬁcation of speciﬁc microorganisms is being used in-

creasingly mainly because it is a quicker test than the MTF. Colilert and Enterolert are the quanti

tray based tests for E. Coli and Enterococcus. This method involve the use of speciﬁc enzymes

and overcomes the drawbacks of the MTF which include false positives and negatives due to the

more generic nature of the media used.

While the above methods are used for quantifying the coliforms, the Presence - Absence Method

below is to assess the presence or absence of bacteria as required by the Revised Total Coliform

Rule.

Presence - Absence (P-A) Method

• The Presence - Absence (P-A) Method for total coliform is based on two premises:

1. No coliform bacteria should be present in 100 mL of drinking water, and

2. If one viable cell is present it will multiply to give a population of cells that will

ferment lactose to produce acid and gas.

•

P-A Method is a simple modiﬁcation of the multiple tube (MPN) method. P-A broth con-

tains lactose and a pH indicator, which will change from purple to yellow if lactose is

fermented and acid is produced. To this P-A broth, the compound MUG has been added.

This initially colorless compound can be hydrolyzed by the E. coli to form a compound

that ﬂuoresces under long UV light (336 nm). Observing for ﬂuorescence emission using a

long-wave (e.g., 365 nm) UV lamp is a sensitive way to conﬁrm the presence of E. coli in

water samples.

•

The procedure involves addition of 100 ml of sample to 50 ml of sterile P-A broth and then

incubating the inoculated broth at 35 deg. C and inspected after 24 and 48 hours. Upon

incubation, a positive result is indicated by the formation of a distinct yellow coloration of

the media and/or gas formation which is indicated by foaming of the media upon gentle

shaking of the bottle.

Besides the P-A broth, the Colilert test enzymes (used in the above Quanti-Tray test) can

be used to test for the Presence-Absence of coliforms. The colilert enzyme is added to

Chapter 3. Water Quality & Laboratory Procedures

100 ml water sample in a sterile, non-ﬂuorescing vessel and incubated at 35 Deg. C for

24 h. The results are read at 24 h (before 28 h) and compared against the comparator. If

no yellow color, the test is negative, If the sample has a yellow color equal to or greater

than the comparator, the presence of total coliforms is conﬁrmed. If yellow, check for blue

ﬂuorescence by placing a 6W, 365 nm UV light within 5 inches of the sample. If blue

ﬂuorescence is greater or equal to the ﬂuorescence of the comparator the presence of E.

coli is conﬁrmed.

3.6 Sampling

•

Field or laboratory measurement of a certain parameter is critical in water treatment and

distribution operations to obtain information about characteristics of water.

A sample is a small part of the whole representing the whole. Thus, a sample needs to

be such that it truly represents the entire population – which could be either a treatment

process stream or what is provided to the end user.

•

• As not all water is analyzed, a sample obtained for analysis must “represent” varying:

–

Locations: Locations should be representative of the majority of their portion of the

Distribution System. Unusual locations should be avoided, as they are not indicative

of the system as a whole. Such locations are often monitored, but not as part of the

routine plan.

– Time periods: Time period samples include:

Grab: Sample taken in a single moment of time.

Composite: Several portions collected over time and/or space.

Continuous

3.6.1 Sampling methods

Grab samples

• A grab sample is a sample collected at a speciﬁc spot at a site over a short period of time.

•

Grab sampling allows for instantaneous analysis of parameters such as pH, dissolved

oxygen, chlorine residual, temperature and other parameters which change rapidly with

time.

• A grab sample represents a snapshot of space and time of a process stream.

Composite Samples

•

A composite sample is a collection of discrete samples are combined over a certain period

or space and therefore represent the average performance of a treatment plant or a process

during the collection period.

• Composite sampling can be either based on:

1. constant time interval (time proportioned sampling)

2. constant volume interval (ﬂow-proportioned sampling), and

3. treatment process space - includes samples taken at different depths

3.6 Sampling

•

Composite samples are typically collected using automated samplers which can be pro-

grammed to collect samples at pre-established time intervals – for time proportional sam-

pling.

•

Time and space composite samples are collected by adding equal volumes of samples

collected from different times or locations.

Flow proportional composite samples comprise of volume of each subsample based on

ﬂow.

Grab Sampling Using a Long Handle Dipper

Automated Sampler

3.6.2 Sampling Precautions and Protocols

•

Samples should represent the major portion of the process or the process stream and

should be taken from places where the mixing is thorough, avoiding dead spots and ar-

eas of heavier or lighter loadings.

•

The collected sample is invariably exposed to conditions very different from the original

source and is subject to change due to chemical and microbiological activity.

Thus, in order to ensure integrity of sample, sample preservation techniques speciﬁc to the

analysis to be performed is needed.

–

The preservation technique should not only allow for stabilizing the parameter to be

analyzed, it should also not interfere with the analyses.

–

The common preservation techniques involve use of proper containers, temperature

control, addition of chemical preservatives, and observance of the recommended

maximum sample holding time.

• Samples cannot be held indeﬁnitely prior to lab analysis

•

Labs must be approved by ELAP: Environmental Laboratory Accreditation Program Labs

must use Standard Methods

•

Chain-of-Custody ensures sample integrity from collection to data reporting Important for

sample control when litigation is involved Must be under a person’s physical possession,

within sight, or secured in a restricted area Receipt and logging of sample at lab Complete

documentation from collection to report

• Sample Containers:

– Typically plastic or glass

– Use proper material for analysis

Chapter 3. Water Quality & Laboratory Procedures

– Use glass for all organic and odor analyses

– Use plastic for metals

– Bacteriological sample containers must be sterile

3.6.3 Microbial sampling

• Always collected as a grab.

•

The sample is obtained from a steady, pencil-width stream from a cold water ﬁxture, only

after it has been in a wide open setting and water to run a minimum of ﬁve minutes to ﬂush

out the bacteria from the surface.

•

A clean, sterile borosilicate glass or plastic bottle containing sodium thiosulfate is used.

Sodium thiosulfate is added to remove residual chlorine which will kill the microorgan-

isms during transit. If the sample is not preserved or maintained under proper conditions

until the test is conducted in the laboratory, the test would provide erroneous results

• Samples must be refrigerated if they cannot be analyzed within 1 hour of collection

•

Samples must be handled with care to prevent contamination and adverse conditions such

as prolonged exposure to direct sunlight

• Maximum holding time for state or federal permit reporting purposes is 6 hours

•

Number of samples collected depends on number of customers served/and is according to

the approved sample siting plan.

The volume for coliform compliance sample must be at least 100ml and no more than

120ml.

Sealed and sterilized sampling bottles - typically, 120 ml with 100 ml marked to provide

space for air is used.

Sodium thiosulfate or some other de-chlorinator is pre-added to the sampling bottle. A

dechlorinator is critical to ensure any chlorine residual is removed from the sample col-

lected.

•

The faucet is opened to obtain a continuous ﬂow of the size of a pencil, the faucet should

not be opened under a strong ﬂow as that could potentially dislodge loose particles/slime

growth in the mains.

When the cap is opened to collect the sample, care needs to be taken to ensure the cap is

not contaminated.

• Fill the bottle to the marked ﬁll-line leaving an air gap - do not overﬁll.

•

The capped bottle should be placed in an iced container and transported to the laboratory

as soon as possible.

• Follow chain of custody and send the bottles to the lab with paperwork.

•

In the laboratory, the samples must be kept at 4 °C or 39 °F and must be analyzed prefer-

ably within 8 hours and never to exceeding 24 hours.

The analytical results shall be reported in terms of the presence or absence of total col-

iforms and E. coli, in the sample, whichever is appropriate.

Monthly sampling results must be submitted to the regulatory agency per established

3.6 Sampling

scheduled.

• Records of bacteriological sampling must be kept for ﬁve years.

•

Repeat sampling: If the result is positive a minimum three samples need to be taken, one

from the original point, one up-stream and one from downstream of the original sample

collection site within 24 hours after the result notiﬁcation from the laboratory.

False positive means that the sample when tested is found to be contaminated but actually

the water is safe.

•

False negative means samples are found to be safe; even though the water is - unsafe to

drink. This can lead to outbreak of diseases and cause customers to lose conﬁdence in their

drinking water supplier. This harms the customer.

3.6.4 Summary of sampling requirements

Parameter

Coliform, Total or Fecal,

Chlorinated Water

Container

Sterile Container w/

thiosulfate

Preservative

Holding Time

Cool to <10 °C. Do not

freeze

8 hrs for source

water compliance

and 30 hours for

drinking water

96 hours

Giardia and Cryptosporid- 10 L plastic con-

Cool to <10 °C . Do not

freeze

ium

tainer

Alkalinity, Turbidity,

Solids , Fluoride

Metals, General

Plastic or Glass

Cool to < 4 °C

Method dependent

6 Months

Plastic or Glass,

Rinsed w/ 1:1

HNO3

Nitric acid to pH <2

Hardness, Total

Nitrogen and phospho-

rous compounds

VOCs, TTHMs

Plastic or Glass

Nitric acid to pH <2

None

Sulfuric acid to pH<2

6 Months

Analyze in 15 min

28 days

Glass bottle

Sodium thiosulfate or

Ascorbic acid if sam-

ple chlorinated and Hy-

drochloric Acid (HCl) to

pH <2 and cool to <4 °C

but do not freeze

14 days

Key Parameters Sampling Requirements

Chapter 3 Assessment

1. Hard water contains an abundance of

a. sodium

b. iron

c. lead

d. calcium carbonate

2. A speciﬁc class of bacteria that only inhibit the intestines of warm-blooded animals is

referred to as?

a. Eutrophic

b. Grazing

c. Salmonella

d. Fecal coliform

e. pathogenic

3. Water with a pH of 8.0 is considered to be

a. acidic

b. basic or alkaline

c. neutral

d. undrinkable

4. Over which water quality indicator do operators have the greatest control?

a. alkalinity

b. pH

c. temperature

Chapter 3. Water Quality & Laboratory Procedures

d. turbidity

5. Which piece of laboratory equipment is used to titrate a chemical reagent?

a. graduated cylinder

b. burette

c. pipet

d. Buchner funnel

6. Which pH range is generally accepted as most palatable (drinkable)?

a. 6.5 to 8.5

b. 4.5 to 6.5

c. 8.5 to 9.5

d. 9.5 and above

e. all of the above

7. Which of the following conditions is favorable for the rapid growth of algae?

a. plant nutrients

b. high pH and water hardness

c. low temperatures and low dissolved oxygen

d. high alkalinity and water hardness

8. Which of the following is the name given for a turbidity meter that has reﬂected or scat-

tered light off suspended particles as a measurement?

a. Hach colorimeter

b. spectrophotometer

c. Wheaton bridge

d. Nephelometer

9. Water hardness is the measure of the concentrations of and dissolved in the water sample.

a. iron, manganese

b. nitrates, nitrites

c. sulfates, bicarbonates

d. calcium & magnesium carbonates

e. ferric chlorides and polymers

10. The electrical potential required to transfer electrons from one compound or element to

another is commonly referred to as

a. oxidation-reduction potential (ORP)

b. voltage potential (OHM/P)

c. resistance-impedance potential

d. microMho differential

11. Water has physical, chemical, and biological characteristics. Which of the following is a

physical characteristic?

a. Coliform

b. Turbidity

c. Hardness

3.6 Sampling

d. All the above

12. Tastes and odors in surface water are most often caused by:

a. clays

b. hardness

c. algae

d. coliform bacteria

13. Which of the following elements cause hardness in water?

a. sodium and potassium

b. calcium and magnesium

c. iron and manganese

d. turbidity and suspended solids

14. When measuring for free chlorine residual, which method is the quickest and simplest?

a. DPD color comparator

b. Orthotolidine method

c. Amperometric titration

d. 1, 2 nitrotoluene di-amine method

Chapter 4

4.1

4.2

4.3

Drinking Water Regulations . . . . . . . . . . . 85

Drinking Water Regulations

Surface Water Treatment Rules

Summary of Requirements under Surface Water

Treatment Rules

4.4

4.5

4.6

4.7

4.8

4.9

Total Coliform Rule

Ground Water Rules

Microbial and Disinfection Byproducts Rules

Other Drinking Water Rules

Recycled Water Regulations

State and Local Drinking Water Regulations

4. Drinking Water Regulations

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams

Ability to read a sample siting plan

Ability to take a lead and copper sample

Knowledge of acute violations

Knowledge of CDPH Water Quality regulations

Knowledge of the deﬁnition of MCL

Knowledge of the major components of the SDWA

Knowledge of the purpose of the SDWA

Knowledge of Total Coliform Rule reporting requirements

Knowledge of Total Coliform Rule sampling requirements

Knowledge of when public notiﬁcation is required

Ability to differentiate between a primary and secondary MCL

Ability to recognize MCL violations

Knowledge of AWWA disinfection standards

Knowledge of Disinfection By-Product Rule sampling requirements

Knowledge of maximum disinfectant residual level for chlorine

Knowledge of reporting and recordkeeping requirements

Knowledge of the relationship between corrosion and lead/copper concentrations

Knowledge of Disinfection By-Product Rule MCL requirements

Knowledge of Disinfection By-Product Rule reporting requirements

Knowledge of lead and copper rule reporting requirements

Knowledge of lead and copper sampling requirements

Knowledge of public notiﬁcation requirements

Ability to perform damage assessment and recovery planning

Ability to train personnel on emergency response procedures

Knowledge of non-compliance penalties

Chapter 4. Drinking Water Regulations

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams (Continued)

Ability to recognize a lead and copper rule violation

Knowledge of notiﬁcation paths (e.g. newspaper, electronic)

Knowledge of required language to use

Knowledge of Air Quality Management regulations

Knowledge of O&M budget components (e.g. labor, professional services, supplies, energy,

water, capital improvement)

Knowledge of RWQCB discharge requirements

Knowledge of the components of a budget (e.g. revenues, expenditures, risk management, insur-

ance costs, depreciation)

Water Treatment System Operator License Exams

Knowledge of disinfection residual requirements

Knowledge of MCLs and MRDLs of disinfectants

Knowledge of drinking water monitoring and reporting requirements

Knowledge of drinking water regulations

Knowledge of notiﬁcation protocol and procedures

Knowledge of NSF Standards

Knowledge of operator certiﬁcation requirements

Knowledge of Primary and Secondary Drinking Water Standards

Knowledge of public notiﬁcation procedures

Knowledge of record keeping requirements

Knowledge of California Waterworks Standards

Knowledge of the Consumer Conﬁdence Report (CCR)

Knowledge of the Disinfectants and Disinfection Byproduct Rule and amendments

Knowledge of the Groundwater Rule

Knowledge of the Lead and Copper Rule

Knowledge of the Surface Water Treatment Rule and amendments

Knowledge of the Total Coliform Rule and amendments

Ability to research and interpret Maximum Contaminant Levels (MCLs)

Knowledge of cryptosporidium action plan

Knowledge of pending regulations

Knowledge of performance standards and removal requirements for surface water treatment

Knowledge of the Filter Backwash Rule

Knowledge of routine sampling requirements

Ability to administer a regulatory compliance program

Knowledge of permit requirements for water operations

Knowledge of pump to waste discharge environmental regulations

Knowledge of regulatory primacy issues

Knowledge of source water replenishment processes

Knowledge of the Sanitary Survey process

Knowledge of the role of Regional Boards in managing contamination sources

Knowledge of the Source Water Assessment Program

Knowledge of the Watershed Survey process

Knowledge of the vulnerability assessment process

4.1 Drinking Water Regulations

•

Drinking water sources which include surface and groundwater sources have inherent

vulnerabilities to contamination and regulations have been established to protect public

health and safety.

Federal Safe Drinking Water Act (SDWA) enacted in 1974 established national enforce-

able standards for drinking water quality and to guarantee that public water systems moni-

tor water to ensure that it meets national standards.

The SDWA prescribes enforceable primary standards for ﬁve major categories of drinking

water contaminants consisting of Inorganic Chemicals, Organic Chemicals, Radionuclides,

Microorganisms, Disinfectants and Disinfection Byproducts.

The SDWA delegates responsibility for administering the provisions of the act to the US

Environmental Protection Agency (USEPA).

• The enforcement of SDWA requirements is delegated by the USEPA to individual states

•

Individual states are provided the opportunity to set and enforce their own drinking water

standards for public water systems if the standards are at a minimum as stringent as EPA’s

national standards.

A primacy agencyis the agency with primary responsibility for implementing the SDWA.

Most states and the U.S. territories have been approved to exercise primary responsibility

in their jurisdictions. Exceptions are the state of Wyoming and the District of Columbia,

which are implemented by EPA.

•

In the SDWA, a Public Water System is deﬁned as a system that supplies piped water for

human consumption and has at least 15 service connections or serves 25 or more persons for

60 or more days of the year.

Community Water System

A community water system is a public water system that has 15 or more service

connections and is used by year-round residents or serves 25 or more residents year round

These include city, county, regulated utilities where people live.

Non-Community Water System

Non-community water system means a public water system that is not a community water

system. These are systems with 15 or more connections used by travelers or intermittent users

at least 60 days of a year or serves a daily average of at least 25 persons at least 60 days a year

A non-community water system can be either:

Transient Non-Community Water System

Include entities like rural gas stations and National parks that provide their own potable

water source. Here most people that consume the water neither reside nor regularly spend

time there.

Non-Transient Non-Community Water System

Chapter 4. Drinking Water Regulations

Non-transient non-community water system means a public water system that is not a com-

munity water system and that regularly serves at least 25 of the same persons over six months

per year. These include places schools and businesses that provide their own water and the

same people have a regular opportunity to consume the water, but do not reside there.

Water systems operated by private homes, groups of fewer than 15 homes using the same

well, and summer camps that operate for fewer than 60 days per year are not covered under

the purview of the SDWA but are generally under some degree of supervision by a local,

area, or state health department.

•

Water treatment standards are set and enforced by the state’s nine regional water quality

control boards in consultation with the California Department of Public Health. The nine

regional boards are part of the State Water Board.

4.1.1 National Primary Drinking Water Regulations

•

National Primary Drinking Water Regulations (NPDWR) is for contaminants – chemicals

and microorganisms - found in drinking water and known to present adverse health effects

to humans.

• The contaminants are divided into two groups based upon its effect on human health:

1. : Acute - effects occur within hours or days of the time a person consumes a contami-

nant

2. Chronic - effects occur over the course of many years after people consume a con-

taminant at levels over EPA’s safety standards.

• NPDWR are legally enforceable drinking water standards.

• The NPDWR standard can be either:

1. Maximum Contaminant Levels (MCLs) - the maximum permissible level of a con-

taminant in water which is delivered to any user of a public water system, or

2. Treatment technique which is a drinking water treatment requirement typically used

when setting an MCL would be too difﬁcult or when compliance with an MCL would

be too costly.

•

Additionally, Maximum Contaminant Level Goal (MCLG) - the maximum level goal

is set at a level where there are no known, or anticipated health effects. For suspected

carcinogens and other similar contaminants, the MCLG is set at zero.

Drinking water must be monitored to ensure that it meets all applicable MCLs. Recurring

sampling every three-years is stipulated.

•

The 90 Primary Contaminants identiﬁed by the EPA are grouped into three major cate-

gories:

1. Chemical Contaminants

– Inorganic chemicals

These contaminants are mostly heavy metals.

They may enter the water supply naturally through ground water formations

4.1 Drinking Water Regulations

or from mining runoff and industrial discharges.

Nitrates are the only chemical contaminant that represent an immediate

health risk. Pregnant mothers and infants under 18 months can develop a

condition known as “Blue Baby Syndrome”. The presence of nitrates in the

bloodstream reduces oxygen uptake that gives the skin a blue tint.

– Organic chemicals

These contaminants include herbicides and insecticides that are primarily

used in agriculture applications, organic solvents used in industrial applica-

tions, organic by-products of industrial processes, and chemical by- prod-

ucts from chlorination of drinking water.

Runoff from agricultural spraying or improper application techniques can be

a major source of these contaminants in a surface water supply.

Industrial discharges, accidental spills and improper disposal of hazardous

wastes can also become sources of contamination.

These compounds are grouped together under the headings of Volatile Or-

ganic Compounds (VOCs) and Synthetic Organic Compounds (SOCs).

There are currently 21 regulated VOCs and 30 SOCs that must be analyzed.

–

The chemical contaminants were promulgated in phases collectively called the

Phase II/V Rules or the Chemical Contaminant Rules.

2. Radioactive chemicals

–

Most radioactive substances occur naturally in ground water and in some surface

supplies.

–

Some man-made substances may also enter drinking water supplies from pro-

cessing facilities, mining areas, and nuclear power plants.

3. Bacteriological Contaminants

–

The coliform group of bacteria represents the indicator organisms used in deter-

mining bacteriological contamination. Their presence indicates the possibility

that some pathogenic (disease causing) organisms may also be present.

A public water system is in violation of the E. coli MCL when any of the follow-

ing occurs:

–

(a) The system has an E. coli-positive repeat sample following a total coliform-

positive routine sample;

(b) The system has a total coliform-positive repeat sample following an E. coli-

positive routine sample;

positive routine sample; or

(d) The system fails to test for E. coli when any repeat sample tests positive for

total coliform.

–

The MCL is exceeded when 5% of the required monthly routine (M/R) samples

indicate the presence of Coliform bacteria.

Chapter 4. Drinking Water Regulations

–

The presence of coliform in any sample will require three repeat samples be

taken. These repeat samples must be taken within 24 hrs of notiﬁcation of posi-

tive results.

• Turbidity - Measure of the cloudiness of water.

–

Although turbidity does not represent a health risk by itself, it can shield harmful

bacteria from disinfection processes.

– Turbidity is measured in Nephelometric Turbidity Units (NTU).

– The device used to measure NTU’s is called a nephelometer or turbidimeter.

4.1.2 Secondary Drinking Water Regulations

•

National Secondary Drinking Water Regulations (NSDWRs) (or secondary standards) are

non-enforceable guidelines regulating contaminants that may cause cosmetic effects (such

as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking

water.

•

NSDWRs are recommended standards and water systems are not required to comply with

the established standard. However, states may choose to adopt them as enforceable stan-

dards.

While secondary standards are not federally enforceable, EPA requires a special notice for

exceedance of the ﬂuoride secondary standard of 2.0 mg/L.

4.1.3 Unregulated Contaminant Monitoring Rule

•

Unregulated Contaminant Monitoring Rule (UCMR) is established by the EPA to collect

data for contaminants that are suspected to be present in drinking water and do not have

health-based standards set under the SDWA.

•

Data are collected through UCMR is to support the determination of whether to regulate

particular contaminants in the interest of protecting public health.

4.1.4 Community Conﬁdence Reports

Every public water system or community water supplier must provide an annual report, some-

times called a Consumer Conﬁdence Report (CCR), to its customers. The report provides infor-

mation on local drinking water quality, including the water’s source, contaminants found in the

water, and how consumers can help protect their drinking water

4.2 Surface Water Treatment Rules

• Surface Water Treatment Rules (SWTRs) are a suite of rules.

•

SWTR applies to all public water systems (PWSs) using surface water sources or ground

water sources under the direct inﬂuence of surface water (GWUDI)

•

GWUDI is located close enough to nearby surface water to receive direct surface water

recharge. Such groundwater source is considered at risk to certain contaminants which are

4.2 Surface Water Treatment Rules

not normally found in true ground waters, but are often found in surface waters.

• GWUDI is also called Subpart H systems.

•

The purpose of SWTRs is to reduce illnesses caused by pathogens in drinking water. The

disease-causing pathogens include Legionella, Giardia lamblia, and Cryptosporidium.

The regulations also protect against contaminants that can form during drinking water

treatment.

•

The SWTRs requires water systems to ﬁlter and disinfect surface water sources. Some

water systems are allowed to use disinfection only for surface water sources that meet

criteria for water quality and watershed protection.

• SWTRs include the following rules:

Figure 4.1: Summary of Water Regulations

4.2.1 Surface Water Treatment Rule

• Adopts a "Multiple Barriers" approach which relies on:

–

Pathogen removal Requires systems to ﬁlter unless speciﬁc avoidance criteria is

met.

– Pathogen inactivation Requires all systems to disinfect.

• Awards "Credits" for both above.

Chapter 4. Drinking Water Regulations

•

Requires most water systems to ﬁlter and disinfect water from surface water sources or

GWUDI

Establishes maximum contaminant level goals (MCLGs) for viruses, bacteria and Giardia

lamblia

Included treatment technique (TT) requirements for ﬁltered and unﬁltered systems to

protect against adverse health effects of exposure to pathogens

4.2.2 Interim Enhanced Surface Water Treatment Rule

•

The 1998 Interim Enhanced Surface Water Treatment Rule (IESWTR) increased the level

of protection from exposure to Cryptosporidium and other pathogens in drinking water

supplies through improvements in ﬁltration at water systems, provided under the original

SWTR.

•

IESWTR applies to all public water systems using surface water, or GWUDI, that serve

10,000 or more persons

The SWTR and the Interim ESWTR includes the following general requirements in order

to minimize human exposure to microbial contaminants in drinking water:

4.2.3 Long-Term 1 Enhanced Surface Water Treatment Rule

•

The Long-Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR) applies to all

public water systems using surface water, or GWUDI, serving fewer than 10,000 persons

The LT1ESWTR builds upon the framework established for systems serving a population

of 10,000 or more in the Interim Enhanced Surface Water Treatment Rule (IESWTR).

While there are small differences between the LT1ESWTR and IESWTR, these differences

reﬂect an effort to reduce burden for small systems while still maintaining a comparable

level of health protection.

4.2.4 Long-Term 2 Enhanced Surface Water Treatment Rule

•

The Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) applies to all

PWSs that use surface water or GWUDI

• Targets additional Cryptosporidium treatment requirements to higher risk systems

• Requires provisions to reduce risks from uncovered ﬁnished water storage facilities

•

Provides provisions to ensure that systems maintain microbial protection as they take steps

to reduce the formation of disinfection byproducts

4.3 Summary of Requirements under Surface Water Treatment Rules

• Utilities are required to achieve at least:

– 99.9% removal and/or inactivation of Giardia lamblia cysts (3-log removal)

– Minimum 99.99% removal and/or inactivation of viruses (4-log removal)

– A 2-log removal of Cryptosporidium.

4.3 Summary of Requirements under Surface Water Treatment Rules

• Control of Cryptosporidium:

– The maximum contaminant level goal (MCLG) is set at zero.

– Filtered systems must physically remove 99% (2-log) of Cryptosporidium.

–

Unﬁltered systems must update their watershed control programs to minimize the

potential for contamination by Cryptosporidium oocysts

• Removal credit:

–

The level of removal credit given a utility for both Giardia lamblia and viruses is

determined by the type of treatment process used.

For a conventional water treatment plant the SWTR provides a 2.5-log removal credit

for Giardia lamblia and a 2.0-log removal credit for viruses.

water treatment plants meeting the turbidity performance standard of 0.3 NTU in

95% of the monthly measurements also get credit for a 2-log reduction in Cryp-

tosporidium.

• Disinfection credit:

–

Disinfection during conventional treatment (assuming all operational criteria and

performance standards are met), must achieve 0.5-log inactivation of Giardia lamblia

and 2.0-log inactivation of viruses.

–

As a substitute to actually measuring the inactivation of Giardia lamblia and viruses

achieved at a treatment plant, the SWTR established the concept of CT to evaluate

inactivation. CT is the product of the concentration of disinfectant remaining at the

end of a treatment process (“C” in milligrams per liter) and the contact time in which

10% of the water passes through the treatment process (“T” or “T10” in minutes).

The SWTR provides tables which identify the log removal of both Giardia lamblia

and viruses achieved for a calculated CT value based on the type of disinfectant, the

water temperature, and pH.

• Turbidity monitoring requirements include:

–

For treatment plants using conventional treatment or direct ﬁltration, a turbidity

performance standard for the CFE of 1 NTU as a maximum, and 0.3 NTU as a maxi-

mum in 95 percent of monthly measurements, based on 4-hour monitoring.

Continuous monitoring of individual ﬁlter efﬂuent (IFE) turbidity in conventional

and direct ﬁltration plants and recording of IFE turbidity readings every 15 minutes.

–

• Reporting and recordkeeping requirements include:

–

PWSs must report turbidity measurements related to CFE monitoring to the state

within 10 days after the end of each month the PWS serves water to the public.

PWSs must keep CFE turbidity monitoring records and any other turbidity analyses,

with the exception of IFE monitoring records, for at least 5 years.

–

– PWSs must keep records from IFE turbidity monitoring for at least 3 years.

•

If a system meets the turbidity performance standard of 0.3 NTU in 95% of the samples

100

Chapter 4. Drinking Water Regulations

taken each month (never to exceed 1 NTU) than the system gets credit for achieving the

2-log reduction in Cryptosporidium.

•

PWSs using alternative ﬁltration techniques [deﬁned as ﬁltration other than conventional,

direct, slow sand, or diatomaceous earth (DE)] must demonstrate to the state the ability

to consistently achieve 2-log removal of Cryptosporidium and comply with speciﬁc state-

established CFE turbidity requirements.

The required level of removal/inactivation must occur between the point where the raw

water is not longer subject to surface water runoff and the point at which the ﬁrst customer

is served.

•

The disinfectant residual entering the distribution system must not fall below 0.2 mg/L for

more than 4 hr during any 24- hr period.

A disinfectant residual must be detectable in 95% of distribution system samples. A het-

erotrophic plate count (HPC) concentration of less than 500 colonies per milliliter can

serve as a detectable residual if no residual is measured.

• Each utility must perform a watershed sanitary survey at least every 5 years.

Figure 4.2: SWTR Auto Removal Credits

TCR/ Nitrate/Nitrite

Sanitary Survey

Total Coliform Bacteria1

Nitrate (NO₃)

Nitrite (NO₂)

Reporting

CWS

NTNCWS

TNCWS

Every 5 years

Monthly

Annually

1 sample record

TNCWS

Every 3 years

Monthly

Every 5 years

Monthly

Quarterly²

1 sample record

CWS

Quarterly²

1 sample record

NTNCWS

Continuous or grab samples Continuous or grab samples Continuous or grab samples

(Frequency determined by population and ﬁltration type.)

Turbidity

Fluoride – if added

Daily

Continuous or grab samples Continuous or grab samples Continuous or grab samples

(Pop determines how many times a day chlorine is measured.)

Entry Point Chlorine – if chlorine is added

Distribution System Chlorine3

Consumer Conﬁdence Report

Disinfection/Disinfectant Byproducts

Monthly

Annually

CWS

Monthly

Annually

Monthly

NTNCWS

Annually

Quarterly

Monthly2

Monthly

NTNCWS

Annually

Once per period

Every 6 months²

NTNCWS

Quarterly²

Quarterly

Annually

TNCWS

Annually

Quarterly

Pop <500

Annually

Total Trihalomethanes (TTHM/HAA5) Pop 500 - 9,999 Quarterly

Pop 10,000

Quarterly

Monthly2

Monthly

TOC and Alkalinity

Bromate (Ozone plants only)

Inorganic Chemicals

All Primary

Arsenic

Asbestos

Lead and Copper1

Organic Chemicals

Pesticides (SOCs) and Other Organics

CWS

TNCWS

Annually

Once per period

Every 6 months²

CWS

TNCWS

Quarterly²

Quarterly

Annually

CWS

Volatile Organic Chemicals (VOCs)

Radionuclides

NTNCWS

Gross Alpha Radioactivity

Radium 226, Radium 228, Uranium

Quarterly

1 Number of samples is based on population. 2 May be reduced if certain criteria are met.

3 Distribution point chlorine test is required at the same time and location as total coliform samples are collected.

Cycle – 3 years; Period – 9 years

Table 4.1: SWTR sampling and testing schedules for surface water and GUDISW

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Chapter 4. Drinking Water Regulations

Figure 4.3: Summary of Total Coliform Rule Requirements

4.4 Total Coliform Rule

•

The 1989 Total Coliform Rule (TCR)promotes surveillance of distribution system water

quality targeting fecal matter and/or pathogens.

Rule requires collection of monthly samples that are representative of water throughout the

distribution system as identiﬁed in its approved Sample Siting Plan.

For systems serving >1,000 people, number of monthly samples that need to be collected

is based upon the population served.

The presence of total coliforms is a warning sign that the system is vulnerable to contami-

nation. It does not necessarily mean that the system is contaminated.

• If sample is total coliform (TC) positive:

A. Conduct follow up testing:

1. In the same sample, determine fecal coliform (FC) or E. Coli (EC).

2. Collect a second sample within 24 hours, and reanaylze TC and FC/EC.

B. The system is not in compliance if:

i. The analysis and reanalysis of a given sampling location are TC positive (TC[+])

both times and FC[/EC+] at least one of these times. OR

ii. More than 5 percent of all monthly samples for a 12-month period are TC[+].

4.4.1 Revised Total Coliform Rule

•

The 2013 Revised Total Coliform Rule (rTCR)revises the 1989 Total Coliform Rule

(TCR) and is applicable to all PSWs.

•

Establishes a zero MCL and MCLG for EC and eliminated MCLG and MCL for TC. EC

being a more speciﬁc indicator of fecal contamination and potentially harmful pathogens

4.4 Total Coliform Rule

103

than TC and also many of the organisms detected by total coliform methods are not of

fecal origin and do not have any direct public health implication.

•

The revised rule changes total coliform detection from a MCL to a Treatment Technique

Trigger, requiring the PWS to perform a system review and ﬁx any potential breaches in

the microbiological barriers. Detection of E. coli during sampling indicates the exceedance

of the MCL. These detections also trigger an inspection and correction of any sanitary

defects found. The rTCR also increases monitoring for many systems experiencing compli-

ance issues or that do not have a microbiologically protected source.

•

Requirements for monitoring TC and EC according to a sample siting plan and schedule

speciﬁc to the PWS.

• Requires sampling site representative of the entire distribution system.

•

Eliminated TCR’s public notiﬁcation requirements based only on the presence of TC and

instead requires public notiﬁcation when:

1. When an an EC MCL violation occurs OR

2. When a PWS fails to conduct the required assessment and corrective action.

Uses vulnerable PWS to initiate a "ﬁnd and ﬁx" approach to address fecal contamination

that could enter the distribution system.

•

rTCR requires PWS to perform assessments to identify sanitary defects - that could pro-

vide a pathway of entry for microbial contamination, or those that indicate failure (existing

or potential) of protective barriers against microbial contamination, and subsequently take

action to correct them.

• There are two levels of assessments based on the severity or frequency of the problem:

1. A Level 1 assessment is required if:

–

For systems taking 40 or more samples per month, the utility exceeds 5.0 per-

cent total coliform-positive samples for the month; or

For systems taking fewer than 40 samples per month, the utility has two or more

total coliform-positive samples in the same month; or

The Utility fails to take every required repeat sample after any single routine

total coliform-positive sample.

2. Level 2 which is an in-depth examination of the distribution system, water sources,

treatment facilities, storage facilities and relevant operational practices at a public

water system (PWS) conducted by an assessor - state or state-approved entity. Level

2 assessment is triggered by an E.Coli MCL violation or a second Level 1 assessment

in a 12-month period or in two consecutive years.

3. When sanitary defects are identiﬁed during a Level 1 or Level 2 Assessment, they

should be corrected as soon as possible to protect public health.

•

A public water system will receive a Treatment Technique violation when any of the fol-

lowing occur:

– Failure to conduct a Level 1 or Level 2 Assessment within 30 days of a trigger.

–

Failure to correct all sanitary defects from a Level 1 or Level 2 Assessment within 30

104

Chapter 4. Drinking Water Regulations

days of a trigger or in accordance with the state-approved time frame.

–

Failure of a seasonal system to complete state-approved start-up procedures prior to

serving water to the public.

4.4.2 Filter Backwash Recycle Rule

•

Filter Backwash Recycle Rule (FBRR)applies to all public water systems using conven-

tional or direct ﬁltration to treat surface water, or GWUDI, regardless of size

Requires PWSs to review their backwash water recycling practices to ensure that they do

not compromise microbial control

Requires recycled ﬁlter backwash water to go through all processes of a system’s conven-

tional or direct ﬁltration treatment.

4.5 Ground Water Rules

The Federal Ground Water Rules (GWR) rule applies to public water systems that use

ground water as a source of drinking water.

• Goal of the GWR is increased protection against microbial pathogens.

•

Ground water systems that are at risk of fecal contamination must take corrective action.

Corrective action reduces potential illness from exposure to microbial pathogens. The

• The GWR relies on four major components:

1. Routine sanitary surveys of systems that require the evaluation of critical elements

of a public water system and the identiﬁcation of signiﬁcant deﬁciencies (e.g., a well

located near a leaking septic system);

2. Triggered source water monitoring for a system that (not treating drinking water to

remove 99.99 percent (4-log) of viruses) identiﬁes a positive sample during regu-

lar Total Coliform monitoring or assessment monitoring (at the option of the state)

targeted at high-risk systems

3. Corrective action is required for any system with a signiﬁcant deﬁciency or source

water fecal contamination; and

4. Compliance monitoring to ensure that treatment technology installed to treat drinking

water reliably achieves 99.99 percent (4-log) inactivation or removal of viruses.

•

In California, the Sustainable Groundwater Management Act (SGMA)sets a timeline to

identify responsible local agencies – which will work as a team – the means to reverse

overdrafted conditions in certain areas and to ensure the 127 “high and medium priority”

groundwater basins or sub-basins not in overdraft reach sustainability by 2040.

4.6 Microbial and Disinfection Byproducts Rules

•

The Microbial and Disinfection Byproducts Rules (MDBPs) include Stage 1 and Stage 2

Disinfectants and Disinfection Byproducts Rules (DBPRs)

4.6 Microbial and Disinfection Byproducts Rules

105

Table 4.2: Disinfectant MRDLs

•

As disinfectants can react with naturally-occurring materials in the water to form byprod-

ucts including:

– Trihalomethanes (THM),

– Haloacetic acids (HAA),

– Chlorite, and

– Bromate.

The Stage 1 and Stage 2 DBPRs are intended to minimize the public health risk from

DBPs and disinfectants that are used to control pathogens.

• Under these rules, EPA established:

–

Maximum residual disinfectant levels (MRDLs) for chlorine, chloramines and chlo-

rine dioxide, and

– MCLs for DBPs - chlorite, bromate, TTHM and HAA5.

•

These Rules apply to all Community Water Systems (CWS) and Non-Transient Non-

Community Water Systems (NTNCWS) that add/deliver a primary or residual disinfectant,

and TNCWs that use chlorine dioxide.

• This Rule does not apply to water systems that use ultraviolet (UV) light.

•

The maximum residual disinfectant levels (MRDLs), and maximum residual disinfectant

level goals (MRDLGs) for the three chemical disinfectants are listed in Table 4.2.

• The MCLs for DBPs are listed in Table 4.3.

•

Compliance is based on a running annual average (RAA) calculated quarterly, locational

running annual average (LRAA) calculated quarterly, a single sample result or an aver-

age of a selected number of samples, depending on which disinfectant or DBP is being

monitored.

• If the creation of these by-products causes the system to exceed the MCL for Total TTHMs

(0.1 mg/l or 100 ppb), the system will be required to change to a different means of disin-

fection.

• Total chlorine residuals are also limited to a maximum of 4.0 mg/l.

• The D-DBP rule currently only applies to systems serving a population over 10,000.

106

Chapter 4. Drinking Water Regulations

Table 4.3: Disinfectant By-products MCLs

4.7 Other Drinking Water Rules

4.7.1 Lead and Copper Rule

•

The objective of the 1991 Lead and Copper Rule (LCR) is to control corrosiveness of the

ﬁnished water in drinking water distribution systems to limit the amount of lead (Pb) and

copper (Cu) that may be leached from certain metal pipes and ﬁttings in the distribution

system.

•

Applies to all community water systems (CWSs) and non-transient non-community water

systems (NTNCWSs)that use ground water as a source of drinking water.

Establishes action level (AL) of 0.015 mg/L for Pb and 1.3 mg/L for Cu based on 90th

percentile level of tap water samples. The rule also establishes an MCLG of zero for lead.

The lead action level is a measure of the effectiveness of the corrosion control treatment in

water systems. The action level is not a standard for establishing a safe level of lead in a

home.

•

Number of samples is based on system size - population served and Systems must conduct

monitoring every 6 months unless they qualify for reduced monitoring.

Utilities are required to identify sampling locations and determining initial tap water Pb

and Cu levels and also monitor other water quality parameters (WQPs) at these locations

to monitor and evaluate the corrosion control characteristics of supplied water.

Each utility must complete a survey and evaluate materials that comprise their distribution

system, in addition to using other available information, to target homes that are at high

risk for Pb/Cu contamination.

•

An AL exceedance is not a violation but can trigger other requirements that include water

quality parameter (WQP) monitoring, corrosion control treatment (CCT), source water

monitoring/treatment, public education, and lead service line replacement (LSLR).

Pb, Cu, and WQPs are initially collected at 6-month intervals. This frequency can be

4.7 Other Drinking Water Rules

107

reduced if action levels are not exceeded and optimal water treatment is maintained.

•

Systems that are in noncompliance and are performing additional corrosion-control activ-

ities must continue to monitor at six-month intervals, plus they must collect WQPs from

distribution system entry points every two weeks.

Table 4.4: Lead and Copper Tap and WQP Tap Monitoring

4.7.2 Radionuclides Rule

•

The 2000 Radionuclide Rule regulates radionuclides in drinking water to protect public

health.

•

Radionuclides are radioactive elements which mostly enters the drinking water source

from natural sources.

• Radiation from radionuclide is known to cause cancer.

• Radionuclide Rule applies only to Community Water Systems.

• The rule extablishes the MCLs for radionuclides.

108

Chapter 4. Drinking Water Regulations

Figure 4.4: Radionuclide MCLs

•

Systems violating the MCL for one of the radionuclide, are required to work with the state

to identify and implement options which may include ﬁnding a better source of water or

blending.

4.7.3 Arsenic Rule

• Arsenic is released to the environment from a variety of natural and anthropogenic sources.

– In the environment, arsenic occurs in rocks, soil, water, air, and in biota.

–

Anthropogenic sources of arsenic relate to its use as wood preservative and in agricul-

ture, livestock, and general industries.

•

There is evidence that associates chronic arsenic ingestion at low concentrations with

increased risk of skin cancer, and that arsenic may cause cancers of the lung, liver, bladder,

kidney, and colon.

• This rule establishes an Arsenic MCL of 10 ppb.

4.7.4 Vulnerability Assessment

•

Under the Public Health Security and Bioterrorism Preparedness and Response Act of

2002, community water systems that serve populations of greater than 3,300 persons are

required to conduct vulnerability assessments.

Vulnerability assessments help water systems evaluate susceptibility to potential threats

and identify corrective actions that can reduce or mitigate the risk of serious consequences

from malevolent acts and natural hazards. .

Such an assessment for a water system takes into account the vulnerability of the water

supply (both ground and surface water), transmission, treatment, and distribution systems.

It also considers risks posed to the surrounding community related to attacks on the water

system.

•

An effective vulnerability assessment serves as a guide to the water utility by providing

a prioritized plan for security upgrades, modiﬁcations of operational procedures, and/or

policy changes to mitigate the risks and vulnerabilities to the utility’s critical assets.

4.7 Other Drinking Water Rules

109

•

Water systems should review their vulnerability assessments periodically to account for

changing threats or additions to the system to ensure that security objectives are being met.

Preferably, a vulnerability assessment is "performance-based,” meaning that it evaluates

the risk to the water system based on the effectiveness (performance) of existing and

planned measures to counteract adversarial actions.

4.7.5 Public Notiﬁcation Rule

• Public Notiﬁcation (PN) Rule requires PWS to notify their customers when:

–

If they violate EPA or state drinking water regulations (including monitoring require-

ments), or

–

If they provide drinking water that may pose a risk to consumer’s health. Water sys-

tems test regularly for approximately 90 contaminants. The monitoring ensures

identiﬁcation of regulated contaminants at levels which may pose a risk to human

health.

• Summary of key public notiﬁcation requirements:

Tier 1: - Immediate Notice, Within 24 Hours

Tier 1 PN is required to be issued as soon as practical but no later than 24 hours after the

PWS learns of the violation or situation including:

–

Distribution system sample violation when fecal coliform or E. coli are present;

failure to test for fecal coliform or E. coli after initial total coliform distribution

system sample tests positive.

–

Nitrate, nitrite, or total nitrate and nitrite MCL violation; failure to take conﬁrmation

sample.

Exceedance of maximum allowable turbidity level, if elevated to a Tier 1 notice by

primacy agency.

– Waterborne disease outbreak or other waterborne emergency.

– Detection of E. coli, enterococci, or coliphage in a ground water source sample.

Tier 2: PN is required to be issued as soon as practical or within 30 days

–

All MCL, MRDL, and treatment technique violations, except where Tier 1 notice is

required.

– Monitoring violations, if elevated to Tier 2 notice by primacy agency.

–

For ground water systems providing 4-log treatment and conducting GWR compli-

ance monitoring, failure to maintain required treatment for more than 4 hours.

Tier 3: Annual Notice Tier 3 PN is required to be issued within 12 months and repeated

annually for unresolved violations.

– All monitoring or testing procedure violations, unless primacy agency elevates to Tier

2, including failure to conduct benchmarking and proﬁling (surface water systems)

and failure to develop a monitoring plan (disinfecting systems).

– Special public notice for availability of unregulated contaminant monitoring results.

–

Special public notice for ﬂuoride secondary maximum contaminant level (SMCL)

110

Chapter 4. Drinking Water Regulations

exceedance.

4.7.6 Sanitary Survey

•

Under the SDWA, every primacy agency is required to have a sanitary survey program

which evaluates the adequacy of the system’s capability for producing and distributing safe

drinking water.

• A sanitary survey must include the following eight essential elements :

1. Water source (protection, physical components, and condition)

2. Water treatment

3. Distribution system

4. Finished water storage

5. Pumps, pumping facilities, and controls

6. Monitoring, reporting, and data veriﬁcation

7. Water system management and operation

8. Operator compliance with state requirements

•

Sanitary surveys are intended to identify deﬁciencies before they present a public health

risk.

Signiﬁcant deﬁciencies are serious sanitary deﬁciencies identiﬁed in water systems which

is determined to be causing, or has potential to cause, the introduction of contamination

into the water delivered to consumers.

•

PWSs must respond in writing to signiﬁcant deﬁciencies identiﬁed in sanitary survey re-

ports no later than 45 days after receipt of the report, indicating how and on what schedule

the PWS will address signiﬁcant deﬁciencies noted in the survey.

Sanitary surveys must be conducted no less than once every three years for community

water systems (CWSs) and no less than once every ﬁve years for non-community water

systems. Primacy agencies may choose to conduct sanitary surveys more frequently than

the minimum requirements.

4.7.7 SDWA Monitoring, Reporting and Recordkeeping Requirements

•

A PWS is required to monitor and verify that the levels of contaminants present in the

water do not exceed the MCL.

If a PWS fails to have its water tested as required or fails to report test results correctly to

the primacy agency, a monitoring violation occurs.

Signiﬁcant Monitoring Violations - are deﬁned as any major monitoring violation that

occurred during the calendar year of the report. A major monitoring violation, with rare

exceptions, occurs when no samples were taken or no results were reported during a com-

pliance period.

•

The Detection Limit for Reporting (DLR) is the detection level set by federal or state

regulation for each reportable analyte for reporting. DLR is the designated minimum level

at or above which any analytical ﬁnding of a contaminant in drinking water resulting from

4.7 Other Drinking Water Rules

111

the mandatory monitoring requirement is to be reported to the State Board.

•

Every Community Water System is required to deliver to its customers a brief annual

water quality report . This report is to include some educational material, and will provide

information on the source water, the level of any detected contaminants, and compliance

with drinking water regulations.

•

Signiﬁcant Consumer Notiﬁcation Violations occurs if a community water system com-

pletely failed to provide its customers the required annual water quality report.

• Record-keeping requirements for a water supplier are summarized below:

Record

Microbiological analyses

Turbidity analyses

Chemical analyses

Sanitary survey documents

Minimum Record Retention Period

5 years

10 years

Variances and exemptions granted 5 years

Tier 1, Tier 2 and Tier 3 Notices

Level 1 and Level 2 assessments

3 years

5 years

Table 4.5: Summary of regulatory record-keeping requirements

112

Chapter 4. Drinking Water Regulations

• Key elements of SDWA monitoring framework are summarized below:

Inorganics

MCL and

no waiver

With waiver

≤

Reliably and

consistently

<MCL

>MCL or not

Reliably and

consistently

<MCL

Surface water

Ground water

Once every 10

years

Once every 10

years

Annual

Quarterly at

each EPTDS

Quarterly at

each EPTDS

Triennial

Volatile Organic Compounds (VOCs)

Waiver with <Detect and <Detect af- Reliably and

consistently Reliably and

≥

Detect not

vulnerability no waiver

analysis

ter at least

three annual <MCL

consistently

samples

<MCL

Quarterly

Surface

water

Ground

water

Once every

10 years

Once every

10 years

Annual

Triennial

Annual

Quarterly

Synthetic Organic Compounds (SOCs)

>Detect or not Re- Waiver with Vul-

Reliably and con-

sistently <MCL

<Detect and no

waiver

liably and consis-

tently <MCL

nerability Assess-

ment every three

years

Annual

Quaterly

Triennial

Pop. >3,300 Semi-

annual Pop. <3,300

Annual

Nitrates

Reliably and 1/2 MCL

consistently OR not Re-

<1/2 MCL

≥

After four

consecutive

quarters

≥

1/2 MCL

with last

four quar-

ters

<MCL

liably and

consistently <1/2 MCL

<MCL

Quarterly

Surface

water

Annual

Ground

water

Annual

Quarterly

Radionuclides

<Detect

≥

Detect and

MCL

≤

1/2 >1/2 MCL and

≤

>MCL

Quarterly

MCL

Every 10 years

Triennial

Table 4.6: Summary of SDWA Monitoring Requirements

4.8 Recycled Water Regulations

113

4.8 Recycled Water Regulations

•

Title 22 of California’s Code of Regulations refers to state guidelines for how treated and

recycled water is discharged and used.

•

State discharge standards for recycled water and its reuse are regulated by the 1969 Porter-

Cologne Water Quality Control Act and the State Water Resources Control Board’s 2019

Water Recycling Policy.

•

Title 22 lists 40 speciﬁc uses allowed with disinfected tertiary recycled water (such as

irrigating parks), 24 speciﬁc uses allowed with disinfected secondary recycled water (such

as irrigating animal feed and other unprocessed crops), and seven speciﬁc uses allowed

with undisinfected secondary recycled water (such industrial uses).

The State Water Board governs the permitting of recycled water projects, develops uniform

water recycling criteria and reviews and approves Title 22 engineering reports for recycled

water use.

4.9 State and Local Drinking Water Regulations

Individual States are responsible for the oversight and enforcement of the federal standards re-

lated to drinking water treatment and distribution. Each State and even local authorities have

the option of adopting more stringent standards, or develop standards regulations for contam-

inants that the federal government has not acted on (perchlorate is a good example of such a

standard). A state cannot set a drinking water standard that is less protective than the US EPA. A

comparison of the Federal and California MCL standards is provided in the following table.

In California, the drinking water treatment and distribution systems are required to be designed,

constructed, operated and maintained per the regulations codiﬁed under Titles 17 and 22 of the

California Code of Regulations (CCR). A Table of Contents for the Drinking Water Regulations

in the CCR is provided in Appendix.

For chemical contaminants not on the MCL list, California Law establishes the following concen-

tration based standards:

1. A Public Health Goal (PHG) : PHG is a non-mandatory goals which reﬂects the risk from

long-term exposure to a contaminant at that level. At the PHG level, the contaminant does

not pose a signiﬁcant health risk. It serves to establish a benchmark concentration level

for the state to establish drinking water standard for that chemical. The current list of

contaminants with PHG is summarized in Tables 4.7, 4.8, and 4.9.

2. Notiﬁcation Levels : Table 4.10 summarizes the current Notiﬁcation Levels. Drinking

water systems are required to issue timely notiﬁcation whenever a chemical contamination

level exceeds the notiﬁcation level.

3. Response Level : This level reﬂects the recommendation for the drinking water system

take the source out of service, if the listed chemical contaminant exceeds the level. Table

4.11 summarizes the current Response Levels.

114

Chapter 4. Drinking Water Regulations

Chemical Name

Public Health Goal (mg/L)

0.004

Alachlor

Aluminum

Antimony

Arsenic

Asbestos

Atrazine

0.6

0.001 (1 ppb)

0.000004

7 million ﬁbers/L

0.00015

Barium

Bentazon

Benzene

Benzo(a)pyrene

Beryllium and Beryllium Compounds

Bromate

Cadmium

Carbofuran

Carbon Tetrachloride

Chlordane

0.2

0.00015

0.000007

0.001

0.0001

0.00004

0.0007

0.0001

0.00003

0.05

Chlorite

Chlorobenzene

0.07

Chromium-hexavalent

Copper

0.00002

0.3

Cyanide

0.15

Dalapon

0.79

Di(2-ethylhexyl)adipate

Di(2-ethylhexyl)phthalate

1,2-Dibromo-3-chloropropane

1,2-Dibromoethane

1,2-Dichlorobenzene

1,4-Dichlorobenzene

1,1-Dichloroethane

1,2-Dichloroethane

1,1-Dichloroethylene

1,2-Dichloroethylene, cis

1,2-Dichloroethylene, trans

2,4-Dichlorophenoxyacetic Acid

1,2-Dichloropropane

1,3-Dichloropropene

Dinoseb

0.2

0.012

0.000003

0.00001

0.6

0.006

0.003

0.0004

0.01

0.013

0.05

0.02

0.0005

0.0002

0.014

Diquat

0.006

Endothall

0.094

Endrin

Ethylbenzene

0.0003

0.3

Table 4.7: Public Health Goals Levels - Table 1 of 2

4.9 State and Local Drinking Water Regulations

115

Chemical Name (Contd.)

Fluoride

Public Health Goal (mg/L)

Glyphosate

0.9

Gross Alpha Particle Activity

Gross Beta Particle Activity

Haloacetic Acids: Dibromoacetic Acid

Haloacetic Acids: Dichloroacetic Acid

Haloacetic Acids: Monobromoacetic Acid

Haloacetic Acids: Monochloroacetic Acid

Haloacetic Acids: Trichloroacetic Acid

Heptachlor

Heptachlor Epoxide

Hexachlorobenzene

Lindane

Hexachlorocyclopentadiene

Lead

N/A

0.00003

0.0002

0.025

0.053

0.0001

0.000008

0.000006

0.00003

0.000032

0.002

0.0002

Mercury (Inorganic)

Methoxychlor

Methyl Tertiary Butyl Ether

Methylene Chloride (Dichloromethane)

Molinate

0.0012

0.00009

0.013

0.004

0.001

Nickel and Nickel Compounds

Nitrate

Nitrite

Nitrite and Nitrate

n-Nitrosodimethylamine

Oxamyl

0.012

45 (10 as nitrogen)

3 (1 as nitrogen)

10 as nitrogen

0.000003

0.026

Pentachlorophenol

Perchlorate

0.0003

0.001

Picloram

0.166

Polychlorinated Biphenyls

Radium-226

Radium-228

0.00009

0.05 pCi/L

0.019 pCi/L

0.03

Selenium

Silvex

0.003

Simazine

0.004

Strontium-90

Styrene

0.35 pCi/L

0.0005

2,3,7,8-Tetrachlorodibenzo-p-dioxin and related compds.

1,1,2,2-Tetrachloroethane

Tetrachloroethylene

Thallium

0.05 picograms/L (pg/L)

0.0001

0.00006

0.0001

Thiobencarb

0.042

Toluene

0.15

Toxaphene

1,2,4-Trichlorobenzene

1,1,1-Trichloroethane

0.00003

0.005

Table 4.8: Public Health Goals Levels - Table 2 of 2

116

Chapter 4. Drinking Water Regulations

Chemical Name (Contd.)

1,1,2-Trichloroethane

Trichloroethylene

Public Health Goal (mg/L)

0.0003

0.0017

1.3

7E-07

0.00006

0.0005

0.0004

0.0001

400 pCi/L

0.43 pCi/L

0.00005

1.8

Trichloroﬂuoromethane (Freon 11)

1,2,3-Trichloropropane

Trichlorotriﬂuoroethane (Freon 113)

Trihalomethanes: Bromodichloromethane

Trihalomethanes: Bromoform

Trihalomethanes: Chloroform

Trihalomethanes: Dibromochloromethane

Tritium

Uranium

Vinyl chloride

Xylene

Table 4.9: Public Health Goals Levels - Table 3 of 3

4.9 State and Local Drinking Water Regulations

117

Chemical

Notiﬁcation Level (milligrams per liter)

Boron

n-Butylbenzene

sec-Butylbenzene

tert-Butylbenzene

Carbon disulﬁde

0.26

0.16

0.8

Chlorate

2-Chlorotoluene

4-Chlorotoluene

Diazinon

Dichlorodiﬂuoromethane (Freon 12)

1,4-Dioxane

0.14

0.0012

0.001

Ethylene glycol

Formaldehyde

0.1

HMX

Isopropylbenzene

Manganese

0.35

0.77

0.5

Methyl isobutyl ketone (MIBK)

Naphthalene

N-Nitrosodiethylamine (NDEA)

N-Nitrosodimethylamine (NDMA)

N-Nitrosodi-n-propylamine (NDPA)

Perﬂuorobutanesulfonic acid (PFBS)

0.12

0.017

0.00001

0.0005

Perﬂuorohexanesulfonic acid (PFHxS) 0.000003

Perﬂuorooctanoic acid (PFOA)

Perﬂuorooctanesulfonic acid (PFOS)

Propachlor

0.0000051

0.0000065

0.09

n-Propylbenzene

0.26

RDX

0.0003

0.012

0.33

0.001

0.05

Tertiary butyl alcohol (TBA)

1,2,4-Trimethylbenzene

1,3,5-Trimethylbenzene

2,4,6-Trinitrotoluene (TNT)

Vanadium

Table 4.10: Notiﬁcation Levels

118

Chapter 4. Drinking Water Regulations

Response Level (Multiples of Notiﬁcation Level)

Chemical

RDX

TBA

100 times the NL

50 times the NL

35 times the NL

30 times the NL

10 times the NL

TNT

NDPA

1,4-Dioxane

NDMA

NDEA

PFOS and PFOA 100 times Cancer risk*

PFHxS

10 times Toxicological endpoint**

All others

10 times the NL

Table 4.11: Response Levels

Chapter 4 Assessment

1. Primary drinking water standards are set to protect the public from illnesses as a direct

result in drinking water that exceeds maximum set levels. Secondary standards were set to

alert the public to

a. the incidences of local cancer numbers

b. dissolved solids in water

c. immediate health concerns

d. radiological conditions concerning drinking water

e. aesthetic issues with drinking water

2. A positive fecal coliform test must be reported to the primacy agency within

a. 8 hours.

b. 12 hours.

c. 24 hours.

d. 48 hours.

3. Which agency sets legal limits on the concentration levels of harmful contaminants in

potable water distributed to customers?

a. National Primary Drinking Water Regulations

b. United States Environmental Protection Agency

c. United States Public Health Service

d. Occupational Health and Safety Organization

4. Which may be substituted for the analysis of residual disinfectant concentration, when

total coliforms are also sampled at the same sampling point?

120

Chapter 4. Drinking Water Regulations

a. Heterotrophic plate count (HPC)

b. Fecal coliforms

c. Giardia lamblia

d. Combined chlorine

5. What does the acronym MCL stand for?

a. Minimum contaminant level

b. Micron contaminant level

c. Maximum contaminant level

d. Milligrams counted last

6. How long do sanitary surveys have to be retained for records?

a. 3 years

b. 5 years

c. 7 years

d. 10 years

7. The most severe water system violation that requires the fastest public notiﬁcation

a. Tier I

b. Tier II

c. Tier III

d. Tier IV

8. The primacy agency may grant a variance or exemption as long as

a. The agency is using the Best Available Technology

b. There is no threat to public health

c. There is never a scenario for a variance or exemption

d. Both A. and B.

9. A public water system that serves at least 25 people six months out of the year

a. Nontransient noncommunity

b. Transient noncommunity

c. Community public water system

d. None of the above

10. Regulations based on the aesthetic quality of drinking water

a. Primary Standards

b. Secondary Standards

c. Microbiological Standards

d. Radiological Standards

11. The lowest reportable limit for a water sample

a. 0.5mg/1

b. Zero

c. Public health goal

d. Detection Level for reporting

12. Primary Standards are based on

4.9 State and Local Drinking Water Regulations

121

a. Color and Taste

b. Aesthetic quality

c. Public Health

d. Odor

13. A disease causing microorganism

a. Pathogen

b. Colilert

c. Pathological

d. Turbidity

14. According to Surface Water Treatment Rule, what is the combined inactivation and re-

moval for Giardia?

a. 1.0logs

b. 2.0logs

c. 3.0logs

d. 4.0 Logs

15. What is the equivalency expressed as a percentage for the SWTR inactivation and removal

of viruses?

a. 99.9%

b. 99.99%

c. 99.0%

d. 99.999%

16. A water agency that takes more than 40 coliform samples must fall under what percentile?

a. 10%

b. 7%

c. 5%

d. No positive samples allowable

17. The National Primary Drinking Water Regulations apply to drinking water contaminants

that may have adverse effects on

a. Water color

b. Water taste

c. Water odor

d. Human health

18. Which of the following is considered an acute risk to health?

a. Two Tier 2 violations

b. One Tier 2 violation

c. Two Tier 1 violations

d. One Tier 1 violation

19. Records on turbidity analyses should be kept for a minimum of

a. 5 years

b. 7 years

122

Chapter 4. Drinking Water Regulations

c. 10 years

d. 25 years

20. Records on bacteriological analyses should be kept for a minimum of

a. 5 years

b. 7 years

c. 10 years

d. 25 years

Chapter 5

Water Treatment . . . . . . . . . . . . . . . . . . . . 119

Background

5.1

5.2

5.3

5.4

5.5

5.6

5.7

Categories of Treatment Methods

Source Management

Surface Water Treatment Processes

Other Treatment Processes

Best Available Technology (BAT)

Chemical Feed Systems

5. Water Treatment

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams

Ability to recognize normal operation of in-line sensors

Ability to troubleshoot a chemical feeder

Knowledge of analysis methods

Knowledge of chemical feeder components

Knowledge of chemical feeder types

Knowledge of required reagents and standards

Knowledge of corrosion control techniques

Knowledge of principles of operation of cathodic protection devices

Water Treatment Operator License Exams

Ability to calculate a dosage for a chemical feeder

Ability to calibrate and adjust a chemical feeder pump

Ability to operate a chemical feeder system

Ability to replace components of a chemical feeder system

Ability to set proper chemical feed rate

Knowledge of chemical feeder calibration and adjustment

Knowledge of the components of chemical feeder systems

Knowledge of the operation of chemical feeder systems

Knowledge of basic unit processes used in treating drinking water

Knowledge of corrective actions to take when regulations are violated

Knowledge of pretreatment procedures

Knowledge of head loss effects on ﬁlters

Knowledge of ﬁlter surface washing methods

Knowledge of ﬁltration mechanisms (absorption, adsorption)

Ability to choose an appropriate disinfectant for a speciﬁc microbial problem

126

Chapter 5. Water Treatment

Expected Range of Knowledge for Water Properties and Sources

Water Treatment Operator License Exams (Continued)

Knowledge of chloramine chemistry

Knowledge of disinfectant byproduct reduction procedures

Knowledge of TOC/Disinfection byproduct correlation

Knowledge of corrosion reduction methods

Knowledge of Best Available Technology (BAT) for common water contaminants

Knowledge of effective removal techniques for common contaminants

Knowledge of hardness removal processes

Knowledge of the components of on-line analyzers

Ability to recognize and correct problems in gravity ﬁlters

Ability to recognize and correct problems in multimedia ﬁlters

Knowledge of backwash sequencing

Knowledge of ﬁlter media types and uses

Knowledge of maximum ﬁltration rates

Knowledge of normal and abnormal ﬁlter media conditions

Ability to calculate ﬁlter media volume and capacity

Knowledge of iron and manganese removal techniques

Knowledge of the aeration process

Knowledge of the operation of blowers and compressors

Ability to discriminate between normal and abnormal operation of blowers and compressors

Knowledge of the components of pressure gauges

Ability to recognize analytical interferences in on-line analyzers

Ability to repair or replace defective parts of on-line analyzers

Knowledge of the operation of on-line analyzers

Knowledge of the operation of an electrical generator

Knowledge of the components of an electrical generator

Ability to conduct a comprehensive performance evaluation of a ﬁlter

Ability to operate an air scour system

Ability to perform a ﬁlter assessment surveillance program

Ability to perform a ﬁlter proﬁle analysis

Ability to recognize and correct problems in granular activated carbon ﬁlters

Knowledge of air scouring systems

Knowledge of ﬁlter media replacement requirements and techniques

Knowledge of ﬁlter porosity

Ability to choose the proper corrosion control chemical for a speciﬁc problem

Knowledge ﬂuoridation chemicals

Knowledge of ﬂuoride chemistry

Knowledge of chemical oxidation techniques and uses

Knowledge of granular activated carbon (GAC)

Knowledge of nitrate removal processes

Ability to replace components of blowers and compressors

Knowledge of the components of blowers and compressors

5.1 Background

127

5.1 Background

•

Purpose of water treatment is to provide safe drinking water that does not contain ob-

jectionable taste, odor or color and provide adequate quantities of water for domestic,

commercial, industrial and ﬁre protection needs.

•

All water produced by public water systems must be drinking water quality, even though

only about 1% of water produced is used for drinking and cooking.

Water may be treated differently in different communities depending on the quality of the

source water that enters the treatment plant. The water that enters the treatment plant is

most often either surface water or ground water. Surface water typically requires more

treatment and ﬁltration than ground water because lakes, rivers, and streams contain

more sediment (sand, clay, silt, and other soil particles), germs, chemicals, and toxins

than ground water.

•

Even though U.S. tap water supplies are considered to be among the safest in the world,

water contamination can still occur. There are many possible sources of contamination,

including:

– Sewage releases

– Naturally occurring chemicals and minerals (for example, arsenic, radon, uranium)

–

Local land use practices (for example, fertilizers, pesticides, livestock, concentrated

feeding operations)

– Manufacturing processes (for example, heavy metals, cyanide)

– Malfunctioning on-site wastewater treatment systems (for example, septic systems)

–

In addition, drinking water that is not properly treated or that travels through an

improperly maintained distribution system (pipes) may also create conditions that

increase risk of contamination.

•

The purpose of water treatment is to condition, modify, or remove undesirable impurities

and to provide water that is safe, palatable, and acceptable to users. Some regulations state

that if the contaminants listed under the various regulations are found in excess of the

Maximum Contaminant Levels (MCLs), the water must be treated to reduce the levels.

Drinking water quality varies from place to place, depending on the condition of the

source water from which it is drawn and the treatment it receives, but it must meet U.S.

Environmental Protection Agency (EPA) regulations. Community water systems follow

the rules set forth by the Safe Drinking Water Act (SDWA).

Many states enforce their own drinking water standards that are at least as protective as

EPA’s national standards. The SDWA rules include guidelines for drinking water quality,

water testing schedules, and water testing methods.

•

The level of treatment and treatment processes used are primarily dependent on the quality

- level of contamination of the source water.

Generally speaking surface waters contain more contaminants compared to groundwater as

surface waters are more exposed to contamination from runoffs etc.

128

Chapter 5. Water Treatment

•

Although groundwaters are succeptible to contamination from seepage and soil percola-

tion, the sediment layers help ﬁlter water naturally.

The quantity and quality of surface water supplies vary more than groundwater, particu-

larly seasonally.

If we assume that the water source used to feed a typical water supply system is groundwa-

ter, which is usually the case in the U.S., a number of common groundwater problems may

require water treatment. Among these other problems are: bacteriological contamination,

hydrogen sulﬁde odors, hard water, corrosive water,and iron and manganese.

Private wells, which are not regulated by the EPA, supply drinking water to over 15 mil-

lion homes. Well owners are responsible for keeping their water clean and safe.

Some water supplies may contain radionuclides (small radioactive particles), speciﬁc

chemicals (such as nitrates), or toxins (such as those made by cyanobacteria). Specialized

methods to control or remove these contaminants can also be part of water treatment.

There are many treatment approaches when it comes to treating a range of problems that

can occur in groundwater. Many of these methods use a combination of technologies.

When considering the appropriate approach, it is important to note that each site should

be treated case by case. Since every site offers a different history, background, and unique

landscape.

•

5.2 Categories of Treatment Methods

Typical treatment methods used can be categorized as:

1. Biological

–

Microbes based biological systems are used for nutrient and organic removals

from drinking water

Typically the biological processes utilize the ﬁxed bioﬁlm - support medium on

which the biomass is attached.

Some applications use suspended growth reactors where the biomass is sus-

pended in the water being treated.

2. Chemical

Chemical oxidants are injected or mixed into groundwater to destroy contam-

–

inants upon contact. Chemical oxidants include oxygen gas, ozone, and other

liquid chemicals.

3. Physical

Most common physical techniques are:

–

Sedimentation: Involves gravity settling of settleable particles by gravitational

force from the water.

Filtration involves removal of pollutants by physical processes including strain-

ing, adsorbtion and absorption.

Dissolved air ﬂotation or Degasiﬁcation: Utilizes pressurized air to remove

5.3 Source Management

dissolved gases is the process of removing dissolved gases from the water.

129

5.3 Source Management

When options are available, source management implies effectively managing wa-

ter sources, to ensure the intake of best possible quality of water from a regulatory

compliance and treatment optimization perspective.

– Examples of source management include:

–

For systems using lake or reservoir sources, selecting the optimum depth from

which to draw water depending on the water quality during that time of year or

for other reasons (e.g. algal bloom, storm upsets, etc).

Systems that have multiple sources may consider blending or alternating surface

and ground water sources to attain the best blended raw water for compliance. If

blended prior to treatment, all water must be treated to surface water standards.

5.4 Surface Water Treatment Processes

5.4.1 Typical surface water treatment process

1. Water is withdrawn from a lake, reservoir or river at the intake

2. It is screened to remove debris

3. Water then enters the ﬂash mixing tank where coagulants and other chemicals are

added

4. Then it is divided into the ﬂocculation basin

5. After ﬂocculation, the water enters the settling basins where solids are removed

6. Filtration then removes particles that are too small to settle by gravity

7. The water is disinfected using some form of chlorine

8. Other chemicals such as ﬂuoride, phosphate corrosion inhibitors or pH adjustment

chemicals may be added

9. After a minimum detention time, the water may be pumped to the distribution sys-

tems Other processes may occur, such as pre-oxidation or activated carbon treatment.

5.4.2 Source Water Treatment

–

Source water treatment in reservoirs or lakes includes treatment to contain algae

growth.

– Algal bloom is a sudden large increase in algae caused by weather or by nutrients.

– Reasons for controlling algae:

Taste and odor problems

Shortened ﬁlter runs

Changes in pH - increases during the day, decreases at night

130

Chapter 5. Water Treatment

Figure 5.1: Conventional Water Treatment

When algae dies, causes depletion of dissolved oxygen (DO)

Organic loading which is DBP pre-cursor resulting in TTHMs.

– Algaecide such as blue stone, copper sulfate (CuSO₄) is used to control algae.

– Action level for copper is 1.3 mg/L· ·

– Copper sulfate dose is usually speciﬁed in terms of pounds/acre.

–

5.4 lbs/acre is common dosage - the rate of application is based on the surface area of

the reservoir not the volume

For water with alkalinify of higher than 150 mg/L, citric acid has to be mixed with

CuSO₄for it to be effective

Applying far more copper sulfate than necessary is uneconomical and ecologically

undesirable. Excessive amounts of copper can kill ﬁsh and other bottom organisms,

and copper tends to accumulate in bottom sediments.

5.4.3 Screening

–

River water (the source of water used in our discussion) frequently contains sus-

pended and ﬂoating debris varying in size from small rags to logs. Screening is usu-

ally the ﬁrst major step where by large and suspended debris in the source water

including sticks, leaves etc. is removed from the water before it enters the plant.

Removing these solids is primarily to prevent damage to downstream equipment

including pumps, prevent deposition of this debris in open channels or pipes, or in

treatment processes.

–

The most important criteria used in the selection of a particular screening system

for are the screen opening size and ﬂow rate. Other important criteria include costs

related to operation and equipment, plant hydraulics, debris handling requirements,

5.4 Surface Water Treatment Processes

131

and operator qualiﬁcations and availability.

–

Depending on the characteristics of the source water, variety of screening devices

including trash rakes, bar screens and wire mesh screens may be used. Very small

screens can be used to screen out elements including algae in the water.

– Typical screening devices used include:

Trash Screens (Rakes) - used to remove rough or large debris. The bar spacing in

Rakes range from 1.5 to 4 inches.

Traveling Water Screens (Bandscreens) - these are placed in a channel of ﬂowing

water to remove ﬂoating or suspended debris.

Figure 5.2: Trash Rake

Figure 5.3: Band Screen

5.4.4 Coagulation and Flocculation

–

A signiﬁcant amount of suspended particles in the raw water are too small to be

ﬁltered or settled out in the sedimentation basin. These particles, termed as colloids

are non-settleable solids and include organic matter, silt, clay.

–

These particles impart turbidity and color to the water and may harbor pathogens and

typically carry a negative electrostatic charge on its surface - negative zeta potential.

The like surface charge on these particles cause electrostatic repulsion (particles keep

132

Chapter 5. Water Treatment

bouncing off one another) which makes these particles difﬁcult to settle.

–

Coagulation and ﬂocculation are sequential processes both of which involve chemical

addition.

For coagulation, either metal salt type coagulant - typically an aluminum salt such as

alum or aluminum sulfate or an iron salt such as ferric or ferrous chloride or sulfate,

polyaluminum chloride or a organic coagulant such as polyDADMAC or polyamine

is used. The coagulant helps coalesce the non-settleable solids into larger particles.

Sodium aluminate is often used as an aide to alum coagulation particularly for cold

water and during lime softening.

–

Coagulation is affected by changes in the water’s pH, alkalinity, temperature, time,

velocity and zeta potential.

The effectiveness of a coagulant is generally pH dependent. Water with a color will

coagulate better at low pH (4.4-6) with alum.

Alkalinity is needed to provide anions, such as (OH⁻) for forming insoluble com-

pounds to precipitate them out. It could be naturally present in the water or needed to

be added as hydroxides, carbonates, or bicarbonates. Generally 1 part alum uses 0.5

parts alkalinity for proper coagulation.

–

The higher the temperature, the faster the reaction, and the more effective is the

coagulation. Winter temperature will slow down the reaction rate

The coagulation process requires rapid mixing of the water upon the addition of the

coagulant followed by a sufﬁcient contact time prior to the ﬂocculation step.

The ﬂocculant which is added after the coagulation step is to make even larger, more

compact and settleable - ﬂoc, from the coagulated solids.

Flocculants are typically long chain organic compounds - polymers with charged end

groups. anionic polymers have a negative end group whereas nonionic polymers

have balanced - positive and negative end groups.

–

For the ﬂoc formed to remain intact, the polymer is gently "folded in" with the coagu-

lated solids. The ﬂocculation is done in a ﬂocculator which have a detention time of

5 -30 minutes and the water is mixed with the polymer using slow moving paddles.

Coagulant aids - chemicals which aid in the coagulation process and strengthening

the ﬂow include:

Alakalinity enahncers - lime, Soda ash, caustic soda and sodium bicarbonate.

Weighting agents - calcimu carbonate and bentonite clay. These are used in

waters which are low in tubidity and high in color which under normal condition

would have formed weak, slow settlling ﬂoc.

Activated sililca - sodium silicate activated by hypochlorous acid is often used as

a coagulant aid with alum.

•

These will usually be used in conjunction with a primary coagulant such as ferric chloride,

ferric sulfate, or alum.

5.4 Surface Water Treatment Processes

133

Untreated Water

Coagulation

Flocculation

Figure 5.4: Coagulation-Flocculation Schematic

•

Determining the amount and type of coagulant used changes based on a variety of process

conditions and quality of water. For example, a heavy rain will greatly impact the inﬂuent,

or raw, water in a municipal treatment plant.

The jar test is a standard method in which various amounts of coagulant and ﬂocculation

times are tested on a raw water sample. There are multiple samples to test before imple-

mentation into a larger volume of the water treatment process.

Figure 5.5: Jar Testing

5.4.5 Clariﬁcation/Sedimentation

•

Clariﬁcation, or sedimentation, is the third step in conventional water treatment, after

coagulation and ﬂocculation and before ﬁltration.

• In the sedimentation basin the ﬂocculated particles settle out under the inﬂuence of gravity.

•

In conventional sedimentation basins the solids drop out (settle) as the water slowly ﬂows

across the basin from the inﬂuent to efﬂuent end.

Sedimentation basins are designed to create conditions in which the water ﬂows very

slowly through the basin, with minimal turbulence.

Conventional sedimentation basins are typically rectangular or cylindrical concrete or steel

vessels which incorporate a horizontal ﬂow of water.

134

Chapter 5. Water Treatment

Cross section of a Rectangular Clariﬁer

Schematic cross section of a circular clariﬁer

Clariﬁer Zones

•

Inlet Zone: is where the water enters the end of a rectangular tank, or the center of a circu-

lar or square tank. The Inlet Zone is designed to accomplish two objectives:

1. Reduce the velocity (dissipate energy in the incoming water). This is accomplished

by the inlet bafﬂe.

2. Distribute the ﬂow evenly using bafﬂes in front of the inﬂuent bafﬂe.

Settling Zone: This is the largest portion of the tank where the water is ﬂowing very slowly

allowing the solids to settle. The clariﬁer is said to be short circuiting if the velocity of

the water is greater in some sections than in others. The water passing through the higher

velocity region will have a reduced detention time and settleable solids will carry through

with this water as it exits the clariﬁer.

Sludge Zone: Sludge zone is the bottom of the tank where the settled solids collect and

compact. Sludge rakes push the sludge to one end or the center of the tank so that it can be

pumped out.

5.4 Surface Water Treatment Processes

135

•

Skimming Zone: The skimming zone is at the surface of the tank for removing scum

removing lighter solids which ﬂoat to the surface.

Outlet Zone: This is the part of the clariﬁer where the settled water leaves the clariﬁer. A

channel called the efﬂuent launder collects the efﬂuent ﬂow and directs it to the clariﬁer

efﬂuent piping. Weirs are installed along the edge of the efﬂuent launder channel to skim

the water evenly off the surface of the tank.

5.4.6 Filtration

Process Basics

•

The SWTR requires the ﬁltration of surface water and ground water under the direct inﬂu-

ence of surface water.

Filtration is the mechanical removal of turbidity particles by passing the water through a

porous medium, which is either a granular bed or a membrane.

• The process of ﬁltration involves straining, settling, and adsorption.

•

Filtration does not remove dissolved solids and by itelf is not effective for the removal of

bacteria.

• In ﬁltration, solids are removed physically by:

– Straining – trapping particles, and

– Adsorption.

• The ﬁltration based treatment process can be either:

1. Conventional - which is a four step treatment process that consists of the treatment

steps of coagualation, ﬂocculation, sedimentation and rapid sand ﬁltration.

2. Direct - where the sedimentation step is omitted. It is for areas with high quality of

water and allows for cost and space savings by eliminating the need for sedimenta-

tion basins.

Figure 5.6: Direct Filtration

136

Chapter 5. Water Treatment

Figure 5.7: Conventional Filtration

• Filters can also be classiﬁed as:

–

Gravity – open to atmosphere and rely on the depth of water above the ﬁlter media to

provide the driving force to pass water through the media.

–

Pressure – utilize a pressure vessel to contain the media and can operate with a much

higher driving force to pass water through the media.

•

Rapid gravity ﬁlters and slow sand ﬁlters are the two major types of ﬁlters used for water

treatment.

• Rapid ﬁltration has following features that allow it to operate at higher water loading rates:

1. A ﬁlter bed of granular material that has been processed to a more uniform size than

typically found in nature.

2. Use of a coagulant to precondition the water, and

3. Mechanical and hydraulic systems to efﬁciently remove collected solids from the

bed.

• The rapid ﬁltration cycle consists of two stages:

1. Filtration stage, when water ﬂows downward through the ﬁlter bed and particles

collect within the bed, and

2. Backwash stage, water ﬂows in the direction opposite to remove the particles that

have collected in the ﬁlter bed. Efﬁcient removal of collected solids is a key compo-

nent of rapid ﬁltration systems, so while the backwashing stage is very short com-

pared to the ﬁltration stage, it is a very important part of the ﬁltration cycle.

•

Rapid ﬁltration is classiﬁed by the level of pretreatment, as presented in Figure 5.8. The

most important factors that determine the required level of pretreatment are the raw-water

quality and the preference and resources of the operating utility.

5.4 Surface Water Treatment Processes

137

Figure 5.8: Rapid Filtration by Pretreatment Level

In a slow sand ﬁlter there is a layer - Schmutzdecke that develops on the top and is made

•

up of microrganisms that feed on and break down organic material that is trapped on the

surface of the ﬁlter. If the source water naturally contain low levels of nutrients, initial

nutrient addition may be needed to develop this layer.

•

The Schmutzdecke enhances the particulate removal. As the Schmutzdecke develops,

the ﬁlter performance – as measured by the turbidity typically improves as the ﬁlter run

progresses.

Filter media can consist of silica sand, greensand, anthracite coal, activated carbon, and

many other types of media.

• Filter media maybe a single media or mixed to provide improved ﬁltration characteristics.

•

Two most common types of granular media ﬁlters include dual-media ﬁlters such as an-

thracite coal and silica sand and tri-media which have anthracite coal, silica sand and ﬁne

garnet.

•

Greensand media which incorporates potassium permanganate and manganese green-

sand which is the mineral called glauconite coated with manganese oxide. Manganese

138

Chapter 5. Water Treatment

greensand is a popular ﬁltration media choice as it removes dissolved iron and manganese,

hydrogen sulﬁde, radium and arsenic. Regeneration of traditional Greensand every six to

twelve months with permanganate is recommended.

•

Activated carbon can be used as a topping for silica sand. The activated carbon does not

only remove solids but also helps adsorb organic contaminants.

Pre-coat ﬁlters, utilize a slurry of raw water with diatomaceous earth (DE) as a pre-coat on

a septum ﬁlter media which then captures the turbidity causing particles from raw water.

The ﬁltration process is followed by a backwash cycle to remove the ﬁltered cake buildup.

Precoat ﬁltration is used to remove very small particulate matter, oil particles, and even

bacteria from water. This method is practical only for relatively small quantities of water

which contain low concentrations of contaminants.

Rapid Sand

Slow Sand

Pre-coat - Diatomaceous Earth

Figure 5.9: Filter Types

• Filters can also be classiﬁed as:

–

Depth ﬁltration – solids are removed within the granular material. Example: Rapid

granular bed ﬁlter

–

Cake ﬁltration – solids are removed on the entering face of the granular material.

Example: Precoat

• The Surface Water Treatment Rule describes ﬁve different types of ﬁltration systems:

– Conventional treatment

5.4 Surface Water Treatment Processes

139

– Direct ﬁltration

– Slow sand ﬁltration

– Diatomaceous earth ﬁltration

– Alternate ﬁltration technologies such as bag ﬁlters and cartridge ﬁlters.

•

Besides using a ﬁlter media, process akin to ﬁltration can also be accomplished using

membranes.

A membrane is a thin layer of material that will only allow certain compounds to pass

through it.

During operation, permeable components pass through the membrane and impermeable

components are retained on the feed side. As a result, the product stream is relatively

free of impermeable constituents and the waste stream is concentrated in impermeable

constituents.

•

Which material will pass through the membrane is determined by the size and the chemical

characteristics of the membrane and the material being ﬁltered.

• Membranes can be classiﬁed into two distinct physicochemical processes:

1. Membrane ﬁltration which encompasses the use of:

(a) Microﬁltration (MF)membrane which function like a sieve. MF membrane pore

size ranges from 0.1 to 1 micrometer (

m); therefore, they remove all particles

bigger than 1

bacteria., and

µm, including Cryptosporidium oocysts, Giardia cysts and all

(b) Ultraﬁltration (UF) membranes which are similar to the microﬁltration mem-

branes except the pore size is smaller - 0.003 to 0.1 m which removes very

small particles including viruses and THM formation precursors.

m, or 1 nm)

pore size and can remove all the particles above nanometer size - besides remov-

ing viruses, cysts, and bacteria they remove some dissolved substances including

divalent ions such as Ca⁺²and Mg⁺²,and are used for softening water and to

reduce the concentration of organic matter to control disinfection by-product

(DBP) formation.

2. Reverse Osmosis (RO) where preferential diffusion of water through a semiperme-

able membrane in response to a concentration gradient.

–

In RO, the feed stream is a solution, or single-phase system, in which the con-

stituents targeted for removal are truly dissolved solutes - ions such as sodium,

chloride and dissolved NOM.

RO membranes are semipermeable - they function as sieves and selective diffu-

sion membranes due to osmosis, allowing for speciﬁc dissolved substances to

pass through.

Osmosis is the passage of water through a semipermeable membrane from the

lower concentration of the dissolved substances to the higher concentration

to equalize the concentration on both sides of the membrane. The force with

140

Chapter 5. Water Treatment

which water ﬂows through the membrane is called osmotic pressure. The greater

the difference in concentration on two sides of the membrane, the higher the

osmotic pressure, and faster is the ﬂow. In reverse osmosis, a pressure higher

than the osmotic pressure is applied on the higher concentration side to force the

water through the membrane in the reverse order.

–

RO membranes are used to treat seawater that has total dissolved solids (TDS) in

the range of 3.5% (35,000 mg/L) and other brackish water (TDS up to 3%).

RO is also capable of removing speciﬁc dissolved contaminants - pesticides,

arsenic, nitrate, radionuclides.

Figure 5.10: Membrane Processes

Operation

•

The removal mechanism in ﬁltration involves straining – trapping larger particles and

through adsorbtion where particles attach themselves to the ﬁlter media

• Typical Filtration Rates:

– Slow Sand: 0.05 gpm/ft²- 3 feet sand

– Rapid Sand: 2 gpm/ft²– 3 feet sand

– Pressure ﬁlters: 3 gpm/ft²

– High Rate: 2-6 gpm/ft²– various media conﬁgurations

•

After a period of operation – ﬁlter cycle, the ﬁlter headloss increases because of the accu-

mulation of the trapped solids.

• Rapid ﬁlters are cleaned by backwashing using an upward, high-rate ﬂow of water

•

Coagulation-ﬂocculation is not required for cake ﬁltration whereas chemical treatment is

required for depth ﬁltration.

Backwashing involves reversing the ﬂow of water through the ﬁlter causing water to travel

from the bottom of the ﬁlter to the top.

Backwash is done at speciﬁc rates in order to most effectively remove the particulate

material. Backwashing process can be augmented by introducing low pressure air into

5.5 Other Treatment Processes

141

the backwash line.

•

Backwash rates of 12-15 gpm/ft²or higher are common for sand, and rates for anthracite

may range from 8 to 12 gpm/ft².

• Wastewater used for the backwash is collected and removed from the ﬁlter.

• Operational Problems

Two common issues include:

–

Air Binding – vacuum generated due to higher water outﬂow than inﬂow causes

violent upheaval impacting the media bed, gravel and/or underdrain.

Mud balls – these are formed as a result of inadequate backwashing and can cause

the the ﬁlter to completely clog-up.

–

5.5 Other Treatment Processes

5.5.1 Pre-chlorination

•

Pre-chlorination - chlorine is added to the incoming ﬂow or, instead, added right before

ﬁltration. Beneﬁts of prechlorination include:

–

Elimination of algae and other forms of aquatic life from the water so they won’t

cause problems in the later stages of water treatment.

– Removal of tastes and odors

–

Control of biological growth throughout the water treatment system, thus preventing

growth in the sedimentation tanks (where solids are removed from the water by grav-

ity settling) and the ﬁltration media (the ﬁlters through which the water passes after

sitting in the sedimentation tanks).

–

Oxidation of iron, manganese and/or hydrogen sulﬁde present in the water into a

precipitate which can be removed in the sedimentation and ﬁltration steps.

5.5.2 Packed Tower Air Stripping

• Water is sprayed on the top of a packed bed while air is blown at the bottom.

•

The packing provide the interface for the transfer of the contaminants from water into the

air phase.

• Air stripping is for removing:

– Volatile solids compounds

– Carbon dioxide

– Hydrogen sulﬁde

– Ammonia

142

Chapter 5. Water Treatment

Figure 5.11: Air Stripper

5.5.3 Aeration

•

In the aeration process the water is either pumped up into the air or allowed to fall over an

aeration device

• Aeration as a water treatment practice is used for the following operations:

– carbon dioxide reduction (decarbonation)

–

oxidation of iron and manganese found in many well waters (oxidation tower). Dur-

ing aeration, iron and manganese get oxidized into an insoluble precipitate which is

removed during ﬁltration.

– ammonia and hydrogen sulﬁde reduction (stripping)

– Aeration is also an effective method of bacteria control.

• Two general methods may be used for the aeration of water:

–

Water-fall aeration Many variations of the water-fall principle are used for this type

of aeration. The simplest conﬁguration employs a vertical riser that discharges water

by free fall into a basin.

–

Air diffusion aeration where air is diffused into a receiving vessel containing counter-

current ﬂowing water, creating very small air bubbles. This ensures good air-water

contact for "scrubbing" of undesirable gases from the water.

5.5.4 Iron and Manganese Sequestration

•

Polyphosphates are used for sequestering iron and magnesium. Sequestration is the ad-

dition of chemicals to groundwater aimed at controlling problems caused by iron and

manganese without removing them.

•

These chemicals are added to groundwater at the well head or at the pump intake before

the water has a chance to come in contact with air or chlorine. This ensures that the iron

5.5 Other Treatment Processes

143

and manganese stays in a soluble form.

•

If the water contains less than 1.0 mg/L iron and less than 0.3 mg/L manganese, using

polyphosphates followed by chlorination can be an effective and inexpensive method for

mitigating iron and manganese problems.

•

No sludge is generated in this method. Below these concentrations, the polyphosphates

combine with the iron and manganese preventing them from being oxidized.

Any of the three polyphosphates (pyrophosphate, tripolyphosphate, or metaphosphate) can

be used.

Applying sodium silicate and chlorine simultaneously has also been used to sequester iron

and manganese. However, while this technique is reliable in the case of iron treatment, it

has not been found to be effective in manganese control.

5.5.5 Fluoridation and Deﬂuoridation

Fluoridation is the use of ﬂuoride in the drinking water. Fluoride is an important component of

bones and teeth. Fluoride deﬁciency causes weaker bones and tooth decay. Too much ﬂuoride

causes skeletal and dental ﬂuorosis, resulting in brittle bones and mottled teeth, respectively. An

effective daily dose of ﬂuoride is 0.9 to 1.7 mg/L. A dose less than 0.7 mg/L does not do the job,

and more than 4.0 mg/L can cause ﬂuorosis leading to irreversible demineralization of bone and

tooth tissues.

EPA has set the maximum contaminant level for ﬂuoride in the drinking water at 4mg/L. Addi-

tionally, a secondary standard of 2.0 mg/L is intended as a guideline for an upper boundary level

in areas which have high levels of naturally occurring ﬂuoride.

Theoretically, any compound that forms ﬂuoride ions in water solution can be used for increasing

the ﬂuoride content of a water supply. Most commonly used chemicals for this purpose include:

•

Fluorosilicic acid ﬂuorosilicic acid, as hexaﬂuorosilicic acid (H₂SiF₆) which is a water-

based solution used by most water systems in the United States. Fluorosilicic acid is also

referred to as hydroﬂuorosilicate, FSA, or HFS.

•

Sodium ﬂuorosilicate as disodium hexaﬂuorosilicate (Na₂SiF₆) which is a dry salt additive,

dissolved into a solution before being added to water, and

Sodium ﬂuoride, a dry salt additive, typically used in small water systems, dissolved into a

solution before being added to water.

In certain areas that have a naturally high level of ﬂuoride in the groundwater deﬂuoridation may

have to occur. Deﬂuoridation methods include:

• Precipitation method utilizes chemical such as Aluminum salts (i.e. Alum) and lime.

•

Ion-Exchange Methods utilizes different ion-exchange materials studied include bone,

bone char and anion and cation exchange resins.

•

Adsorption method uses chemical and physical adosrbents including activated carbon and

alumina (Al₂O₃). Activated alumina is used to treat water with ﬂuoride concentrations

from 4-20 mg/L in an adsorption process.

144

Chapter 5. Water Treatment

Fluoride Dosing Chemicals Safety

• Rubber gloves, coveralls, and protective eyewear should be worn when handling ﬂuoride.

•

Solid forms of ﬂuoride are the most problematic to operators, since inhaling ﬂuoride dust

is very dangerous. A dust collector should be used and a respirator should be worn when

handling ﬂuoride powders.

Liquid forms, such as hydroﬂuosilicic acid, can also be dangerous. Hydroﬂuosilicic acid

produces poisonous fumes which must be vented and which are irritating to the skin. The

liquid itself can cause burns when allowed to touch skin.

The most extreme safety problem when dealing with ﬂuoride is ﬂuoride poisoning, which

can be fatal. However, ﬂuoride poisoning occurs only when a large amount of ﬂuoride -

approximately one tablespoon - is ingested. This is an amount much larger than would

normally be inhaled while handling dry ﬂuorides.

•

Accidental ingestion of ﬂuoride chemicals can occur through contaminated food and drink.

The operator should always wash his hands after handling ﬂuoride chemicals and should

not eat, drink, or smoke in areas where ﬂuorides are used or stored.

5.5.6 Hardness Removal

•

In almost every raw water supply, hardness is present as calcium and magnesium bicarbon-

ate - (Ca/Mg)HCO₃, often referred to as carbonate hardness or temporary hardness. These

compounds result from the action of acidic, carbon dioxide laden rain water on naturally

occurring minerals in the earth, such as limestone.

CO₂+ H₂O = H₂CO₃

H₂CO₃+ CaCO⁻₃= Ca(HCO₃)₂

•

Hardness may also be present as a sulfate or chloride salt, referred to as noncarbonate or

permanent hardness. These salts are caused by mineral acids present in rain water or the

solution of naturally occurring acidic minerals.

• Softening removes hardness and alkalinity making the product water more corrosive.

•

It may be necessary to add corrosion-inhibiting materials to the ﬁnished water to protect

the distribution system and prevent possible simultaneous compliance issues with other

regulations like the Lead and Copper Rule.

•

Another option is to bypass a portion of water around the softening process and blending

the treated and untreated waters are blended to produce an efﬂuent with a total hardness

around 50 to 75 mg/L as CaCO₃.

• Two common methods used to reduce hardness:

1. Cation exchange:

–

In this process the calcium (Ca⁺²) and magnesium (Mg⁺²) ions that cause water

hardness are replaced or exchanged with with a non-hardness ion like sodium.

The exchange medium can be natural “zeolites” or synthetic resin beads that

resemble wet sand and hold loosley the sodium ions provided by dissolving

sodium chloride salt.

5.5 Other Treatment Processes

145

–

As hard water passes through a softener, the calcium and magnesium trade

places with sodium ions.

Eventually when the exchange medium becomes coated with calcium and mag-

nesium ions, it must be recharged or regenerated.

2. Precipitation Softening

–

Here the water is treated with lime or a combination of lime and soda ash (sodium

carbonate, Na₂CO₃).

–

These chemicals react with the hardness and natural alkalinity in the water to

form insoluble compounds (precipitate) which are removed from the water by

sedimentation and, usually, ﬁltration.

–

Waters with moderate to high hardness and alkalinity concentrations (150-500

ppm as CaCO₃) are often treated in this fashion.

Lime removes bicarbonates - which cause carbonate hardness.

Soda ash is used to remove chemicals that cause non-carbonate hardness.

The addition of lime as either hydrated lime (calcium hydroxide - Ca(OH)₂) or

as quicklime (CaO) results in:

Increases the pH of water

Reaction with calcium bicarbonate Ca(HCO₃)⁻typically the major source

of hardness converting it to CaCO₃. For each molecule of calcium bicarbon-

ate hardness removed, one molecule of lime is used.

As the pH increases further, additional Ca(OH)₂will then react with mag-

nesium bicarbonate Mg(HCO₃) ultimately converting it to magnesium hy-

droxide (Mg(OH)₂. For each molecule of magnesium bicarbonate hardness

removed, two molecules of lime are used.

Calcium is removed in the 9.0-9.5 pH range and the pH needs to be at least

10.6 to remove magnesium.

Both CaCO₃and Mg(OH)₂have limited solubility in water and precipitate

out.

Because CaCO₃and Mg(OH)₂precipitates are very slightly soluble, some

hardness remains in the water–usually about 50 to 85 mg/l (as CaCO₃). This

hardness level is desirable to prevent corrosion problems associated with

water being too soft and having little or no hardness.

– Use of lime along with soda ash with results in:

The magnesium non-carbonate hardness such as Mg(SO₄) is converted by

lime to Mg(OH)₂and Ca(SO₄) - a form of calcium non-carbonate hardness

The calcium non-carbonate hardness - CaSO₄is converted by soda ash to

CaCO₃.

For each molecule of non-carbonate calcium hardness removed, one molecule

of soda ash is used.

For each molecule of non-carbonate magnesium hardness removed one

146

Chapter 5. Water Treatment

molecule of lime plus one molecule of soda ash is used.

When water has minimal magnesium hardness, only calcium needs to be

removed. Only enough lime and soda ash are added to water to raise pH

to between 10.3 and 10.6, and calcium hardness will be removed from the

water (but minimal magnesium hardness will be removed).

Extra lime addition is required to raise the pH above 10.6 to precipitate

Mg(OH)₂out of the water.

To improve magnesium reduction, which also improves silica reduction,

sodium aluminate is added. The sodium aluminate provides hydroxyl ion

(OH⁻) needed for improved magnesium reduction, without increasing cal-

cium hardness in the treated water. Additonal beneﬁts of adding sodium

aluminate comes from its formation of aluminum hydroxide which aids ﬂoc

formation, conditions sludge blanket and helps reduce silica.

– The portion of raw water may be bypassed

–

Precipitation softening is often done in conjunction with coagulation and ﬂoccu-

lation.

– The precipitate formed is separated in the sedimentation tank as sludge.

–

The high pH, softened water produced is corrosive and Recarbonation of the

softened water using carbon dioxide (CO₂) is conducted to lower the pH and

thus its corrosivity.

– Lime softening produces large quantity of sludge.

–

The reaction of Quicklime with water leading to the formation of Ca(OH)₂

releases large quantity of heat and is dangerous if left uncontrolled. Also,

Quicklime should never be stored with alum as the water of hydration in

alum will react with quicklime causing an explosion

5.5.7 Corrosion Control

•

Corrosion is the gradual deterioration or destruction of metal surfaces by chemical and

electrochemical processes.

As corrosive water stands or seals in pipes or tanks, it leaches metals from the piping,

tanks, well casing, or other metal surfaces that water is in contact.

Corrosion can happen both from the inside of pipes and ﬁttings and from the outside -

because of the action of the external environment - including soils.

Lead and copper in service lines and household plumbing leach into the drinking water

because of the corrosivity of water.

Lead is a toxic metal that can be harmful to human health even at low exposure levels.

Lead is persistent and can bioaccumulate in the body over time.

The corrosivity of water will depend on the material of construction of the distribution

system components and characteristics of water - water is less corrosive at higher pH and

alkalinity.

5.5 Other Treatment Processes

147

Figure 5.12: Precipitation Softening

148

Chapter 5. Water Treatment

•

Corrosion potential of the water on the distribution system components can be mitigated

by chemical treatment:

–

Adding alkalinity in the form of lime, soda ash, or caustic soda to make the water

stable or slightly scale-forming.

–

Orthophosphates are added to chemically react with lead and copper atoms forming

lead and copper phosphate. The lead and copper phosphate is then electrochemically

drawn back down onto the piping surface, where it forms a tough, water-resistant

coating on the piping.

–

Silicate compounds added to water also inhibit corrosion by forming a thin protective

ﬁlms on pipe walls.

5.6 Best Available Technology (BAT)

Below is the summary of BATs - the very best (state-of-the-art) control and treatment measures

that have been developed, or are capable of being developed, and that are economically achiev-

able, identiﬁed in the California Code of Regulations.

5.6.1 BATs for Inorganics

Chemical Best Available Technologies (BATs)

Aluminum 10

Antimony

Arsenic

Asbestos

Barium

2, 7

1, 2, 5, 6, 7, 9, 13

2, 3, 8

5, 6, 7, 9

1, 2, 5, 6, 7

2, 5, 6, 7

Beryllium

Cadmium

Chromium 2, 5, 6^a, 7

Cyanide

Fluoride

Mercury

Nickel

5, 7, 11

2 b , 4, 6 ^b, 7 b

5, 6, 7

Nitrate

Nitrite

5, 7, 9

5, 7

Perchlorate 5, 12

Selenium

Thallium

1, 2 ^c, 6, 7, 9

1, 5

^aBAT for chromium III (trivalent chromium) only.

^bBAT only if inﬂuent mercury concentrations <10 µg/L.

^cBAT for selenium IV only.

where:

1 = Activated Alumina

2 = Coagulation/Filtration (not BAT for systems <500 service connections)

5.6 Best Available Technology (BAT)

149

Treatment

Method

How It Works

What It Removes

Activated carbon

ﬁltration

As water ﬂows through the ﬁlter contam-

inants adsorb, or stick to, the surface of

activated carbon particles.

Pesticides; organic compounds such as benzene and carbon

tetrachlo- ride; many odors; bacterial or colloidal iron or

tannins when combined with continuous chlorination; radon;

lead or copper if equipped with special media; some other

heavy metals in certain cases; chlorine; chloramines; tri-

halomethanes. Filters with molded activated carbon blocks

will treat Cryptosporidium and Giardia.

Reverse osmosis

(RO)

Contaminants are removed by forcing water

through a membrane which has microscopic

holes. Water molecules pass through the

membrane but larger particles cannot. The

membrane is ﬂushed to remove trapped

contaminants.

Certain tastes; some pesticides; high chloride content; ﬂuo-

ride; nitrate; lead, copper, and other heavy metals; arsenic;

Cryp tosporidium; viruses.

Ion exchange

water softening

As water passes through a resin bed in

the softener, calcium and magnesium in

the water are exchanged for sodium or

potassium which do not create the nuisance

problems associated with hard water.

As water passes through a ﬁlter made of

sand, ﬁlter paper, compressed glass wool or

other straining material suspended particles

such as sand, soil or other particles are

trapped on the ﬁlter.

Hard water (calcium and magnesium); dissolved iron; man-

ganese; will treat cadmium, copper and zinc if operated

properly.

Sediment ﬁltra-

tion

Sediment; acidic water when preceded by soda ash feed;

dissolved iron or manganese when preceded by continuous

chlorination, ozonation or aeration; turbidity.

Distillation

Aeration

Water is heated to create steam which is

then condensed to be collected as treated

water. Contaminants removed remain in

the heating chamber or boil off into the

atmosphere.

Oxygen is introduced into the water by an

aerator. This oxidizes contaminants such as

iron and manganese, causing them to form

solids which can then be ﬁltered out of the

water.

Sediment; high salt content; high total dissolved solids;

pesticides if properly equipped with gas vent; ﬂuoride; nitrate;

lead, copper and other heavy metals; arsenic; bacteria.

Dissolved iron or manganese when followed by sediment

ﬁltration; may help reduce rotten egg odor from dissolved

hydrogen sulﬁde gas; radon.

De-Aeration

Mix air with water to remove dissolved

gases from the water. Aeration and

Dissolved hydrogen sulﬁde gas; radon. De-aeration equip-

ment sometimes are very similar, but are designed for differ-

ent treatment goals.

Continuous

Chlorination

Chlorine is fed or injected into the water

to kill bacteria and other microbial con-

taminants, as well as to oxidize iron and

manganese causing them to form solids

which can then be ﬁltered out.

Dissolved iron or manganese when followed by sediment

ﬁltration; rotten egg odor from dissolved hydrogen sulﬁde gas

or sulfate-reducing bacteria (followed by activated carbon ﬁl-

tration); bacterial or colloidal iron or tannins when combined

with activated carbon ﬁltration; bacteria; Giardia; viruses.

Ultraviolet (UV)

radiation

As water passes through the system, a

special lamp produces ultraviolet light

that kills bacteria and other microbial

contaminants.

Ozonation

Water enters a system where ozone is

produced and mixed with the water, a

chemical form of pure oxygen,

Bacteria; Giardia; Cryptosporidium; viruses; Ozonation

destroys bacteria and other microbial pathogens and oxidizes

compounds such as iron and manganese causing them to form

solids which can then be ﬁltered out using sediment ﬁltration.

Cryptosporidium; Giardia; viruses.

Ultra, micro, and

nano ﬁltration

As water passes through a ﬁlter, suspended

particles are trapped on the ﬁlter. Particles

removed depends upon the size of the pores

in the ﬁlter. Pore sizes from smallest to

largest are nanoﬁltration, ultra ﬁltration and

microﬁltration.

Table 5.1: Summary of Water Treatment Methods

150

Chapter 5. Water Treatment

3 = Direct and Diatomite Filtration

4 = Granular Activated Carbon

5 = Ion Exchange

6 = Lime Softening (not BAT for systems <500 service connections)

7 = Reverse Osmosis

8 = Corrosion Control

9 = Electrodialysis

10 = Optimizing treatment and reducing aluminum added

11 = Chlorine oxidation

12 = Biological ﬂuidized bed reactor

13 = Oxidation/Filtration

5.6.2 BATs for Microbiological Contaminants

Best available technology (BAT) (for a public water system serving more than 10,000 persons),

affordable technology (for a public water system serving 10,000 or fewer persons), treatment

techniques, or other means available for achieving compliance with the E. coli MCL are as fol-

lows:

(a) Protection of wells from fecal coliform contamination by appropriate placement and construc-

tion;

(b) Maintenance of a disinfectant residual throughout the distribution system;

repair procedures, main ﬂushing programs, proper operation and maintenance of storage tanks

and reservoirs, cross connection control, and continual maintenance of positive water pressure in

all parts of the distribution system;

(d) Filtration and/or disinfection of approved surface water, in compliance with Section 64650,

or disinfection of groundwater, in compliance with Section 64430, using strong oxidants such as

chlorine, chlorine dioxide, or ozone; and

(e) For a system using groundwater, compliance with the groundwater portion of a Drinking

Water Source Assessment and Protection Program.

5.6.3 BATs for Radionuclides

Radionuclide

Best Available Technology

Combined radium-226 and radium-228 Ion exchange, reverse osmosis, lime softening

Uranium

Ion exchange, reverse osmosis, lime softening,

coagulation/ﬁltration

Gross alpha particle activity

Reverse osmosis

Beta particle and photon radioactivity

Ion exchange, reverse osmosis

5.7 Chemical Feed Systems

151

5.7 Chemical Feed Systems

•

Chemical feed systems are designed for automated and precise injection (dosing) of chemi-

cals into the water to be treated.

• Chemical feed systems are mainly employed for the following types of water treatment:

– Disinfection

– Flocculation and Coagulation

– Nutrient Removal

– Sludge Conditioning

– Alkalinity Supplementation

– Corrosion Inhibition

•

The chemical feed systems is comprised of different components and is typically designed

to ensure suitability with the chemical dispensed and the environment.

• There are three types of chemicals used by chemical feed systems:

1. Dry Chemicals: These chemicals are in dry, powdered form. Sodium bicarbonate,

calcium hypochlorite, calcium chloride, algaecides, and soda ash are a few popular

types of dry chemicals. Dry chemicals may or may not be mixed with liquids.

2. Liquid Chemicals: These are most common form of chemicals used due to the ease

of use. Aluminum sulfate or liquid alum, 50% sodium hydroxide, and caustic soda

are a few liquid chemicals used regularly.

3. Gaseous Chemicals: Chlorine gas is widely used in water treatment for disinfection.

5.7.1 Key Components of a Chemical Feed System

Delivery Systems

• Feed pumps carry chemicals for dosing.

•

Metering pumps are the most common types of feed pumps used for liquid chemical feed

systems. Types of chemical metering pumps used in the water industry include:

– Diaphragm Pumps:

A diaphragm pump consists of one or more pumping chambers alternately ﬁlled

and discharged by the movement of ﬂexible diaphragms and check valves on the

inlet and outlet.

The diaphragm pump is composed of the following:

· A chamber used to pump the ﬂuid

· A diaphragm or diaphragms operated by either electric or mechanical means

Two valve assemblies: a suction valve assembly and a discharge valve as-

sembly

152

Chapter 5. Water Treatment

Figure 5.13: Air Operated Double Diaphragm Pump

These pumps are widely used to handle mostly all liquid chemicals, as well as

sludges and slurries with ease.

– Peristaltic Pumps:

These pumps are also known as roller pumps because it uses a set of rollers to

pump the ﬂuid.

The chemical ﬂuid to be pumped is contained in a ﬂexible tube, which is posi-

tioned inside a pump casing.

The rotors equipped with rollers compress the tube, thereby forcing the ﬂuid to

move towards the pipe. The pump comes to its original position after the ﬂuid

moves out. This whole process is known as peristalsis.

Peristaltic pumps are suited for applications requiring small feed rates of < 0.1

gallons per hour.

Figure 5.14: Peristaltic Pump

–

Other Metering pumps include: Packed Plunger Pumps, Liquid Gravity Feeders and

Jet Pumps (Eductors)

• For dry chemicals the following types of feeder systems are used:

–

Volumetric Feeders: These feeders dispense an accurate amount of powdered mate-

rial. Volumetric feeders are generally used for feeding dry chemicals such as lime

slaking, lime feed, clay feed, dry polymer, and so on.

–

Gravimetric Feeders: The feeders feed chemicals by weight. Gravimetric feeders

assure accuracy within 1-2%.

5.7 Chemical Feed Systems

153

Volumetric Feeder

Gravimetric Feeder

Figure 5.15: Dry Chemical Feeders

•

Gaseous chemicals are transferred using gas feeders. To ensure safety, particularly when

used in an application involving chemical such as chlorine, these gas systems are used

under vacuum. To use these systems, special equipment and arrangements need to be done.

Self-contained breathing equipment, special containment chorine rooms, chlorine gas

detectors, as well as chlorine air room scrubbers are some of the requirements.

Chemical Storage Systems

Solution tanks are the chemical storage systems used for holding chemical solutions to be fed

into the water. There are three types of chemical storage systems used:

•

Bulk Storage: The storage tank of this type can hold liquid chemicals in bulk. The chem-

icals for treatment are delivered by a carrier or a vendor truck. The tank is usually posi-

tioned near the feed system.

Semi Bulk Storage: This type of storage is ideal for applications that do not use chemical

feeds regularly. Semi bulk storage tanks are designed in such a way that the tanks can be

stored easily by stacking above one another when not in use.

Drum Storage: This was one of the most popular methods of chemical storage until a

few years back. Safe disposal of drums after the end of their lifespan was one of the key

challenges faced by users. To avoid this, nowadays, reusable containers - totes are used.

Accessories

•

Mixers: The job of the mixer is to rapidly disperse the chemical additives to ensure a uni-

form mixture. A rapid (or ﬂash) mixer utilizes speciﬁcally designed impeller to uniformly

disperse and blend chemicals, such as coagulant aids, chlorine, and sulfur dioxide, into the

process stream. Flash mixer can be installed in a tank, process chamber or pipe.

154

Chapter 5. Water Treatment

In-line Flash Mixer

Figure 5.16: Flash Mixers

Process Flash Mixer

• Timers: Timers used to control the function of mixers, as well as the feeding of chemicals.

•

Alarms: Alarms are typically used as monitoring systems for different components of the

chemical dosing system. They can be set to monitor tank levels, chemical feed rates, pump

status, and changed operating conditions. Alarms help to reduce damages caused due to

dry running or change in operating variables, or some unspeciﬁed conditions.

Level Gauges: As the name indicates, these devices are used to monitor the level of chemi-

cals in tanks.

•

Control Panels: The control panel may also contain lights that indicate the status of the

pumps, various alarm conditions, and hour meters.

Types of Chemical Feed Systems

•

Chemicals are fed into the water stream in different ways based on the required feed rate

and feed pump output.

• Typically, solid and liquid chemicals can be fed in any of the following ways:

–

Continuous Feed: This system is commonly used for liquid chemicals, which are

continuously fed into the water tank. This feed system is commonly employed for

deposit control in once-through systems, as well as domestic water chlorination.

The continuous feed may be provided by a gravity drip feed, where the feed rate is

regulated by a needle valve.

–

Shot/slug Feed: The chemical is shot/slug-fed by an on-off control on a feeder pump.

It may also be discharged from a measuring chamber or a calibrated pump. This

type of feeding is widely used in bio-oxidation basins or cooling systems with high

system volume to blowdown ratio.

• For gaseous chemicals dosing, the following two methods are utilized.

–

Solution Feed: This type of feeding is seen in vacuum-type feeders, where gas is

drawn to the piping system by vacuum. If there is any leak in piping then it leads to

vacuum loss, and as a result, the system is shut down for supply. The vacuum feeders

use ejectors to create a vacuum required for operation.

–

Direct Feed: In this feed, gas is fed into the ﬂow stream to be treated. This involves

5.7 Chemical Feed Systems

155

the direct injection of gas under high pressure. This type of feeding is usually re-

stricted to small applications, which have no regular water supply for solution feed.

Chemical control systems

Typical types of chemical control systems include:

•

Manual Controls: This is one of the simplest, yet popular controls employed in the water

industry. The output of the pump is set manually using dials or knobs, and the pump is put

on or off using a manual switch. Sometimes, the power supply on the pump is put on or off

for operating or closing the pump.

•

Automatic chemical dosing control instrumentation is usually set up as either a “feed

forward” or a “feedback” loop.

–

An example of a feed forward loop would be a venturi ﬂow meter which is located

forward of the chlorine feed point sending a signal to change a chlorine dosage based

on a change in ﬂow.

–

An example of a feedback loop would be a chlorine analyzer located downstream of

the chlorine dosage point, changing the chlorine dosage based on a change in residual

downstream of the chlorinator.

•

On-off Constant Rate Mode: In this type of pump control, the pump on and off is auto-

mated. This control is more apt for cooling towers or other similar applications that do not

require a continuous or regular feed of chemicals. In short, it is most suitable for control-

ling acid feed rates at low or high pH setpoints.

Chapter 5 Assessment

1. What is the purpose of coagulation and ﬂocculation?

a. control corrosion

b. to kill disease causing organisms

c. to remove leaves, sticks, and ﬁsh debris

d. to remove particulate impurities and suspended matter

2. How are ﬁlter production (capacity) rates measured?

a. Mgd/sq.ft.

b. Gpm/sq.ft.

c. Gpm

d. Mgd

3. Why should a ﬁlter be drained if it is going to be out-of-service for a prolonged period?

a. to allow the media to dry out

b. to save water

c. to prevent the ﬁlter from ﬂoating on groundwater levels

d. to avoid algal growth

4. Which of the following are commonly used coagulation chemicals?

a. hypochlorites and free chlorine

b. sodium and potassium chlorides

c. alum and polymers

d. bleach and HTH

5. How can an operator tell if a ﬁlter is NOT completely cleaned after backwashing?

158

Chapter 5. Water Treatment

a. the initial headloss is on the high side

b. the backwash rate was too slow

c. mudballs are NOT present

d. backwashing pumping rate is too low

6. Flocculation is deﬁned as

a. the gathering of ﬁne particles after coagulation by gentle mixing

b. clumps of bacteria

c. the capacity of water to neutralize acids

d. a high molecular weight of compounds that have negative charges

7. A multi-barrier water ﬁltration plant that contains a ﬂash mix, a coagulation/ﬂocculation

zone, sedimentation, ﬁltration and a clear well is considered to be a

a. community special treatment plant

b. direct ﬁltration plant

c. reverse osmosis plant

d. conventional ﬁltration plant

e. traditional plant

8. The ﬁltration unit process usually

a. is located at the beginning of a ﬁltration plant

b. follows the coagulation/ﬂocculation/sedimentation processes

c. is located after the clear well area

d. is located on the plant efﬂuent line after the clearwell

9. Filters are generally backwashed when the loss-of-head indicator registers a certain set

value, such as 6-ft, or upon a certain time, say 48-hours, or upon a rise in

a. alkalinity

b. a jar-test result

c. turbidity

d. temperature

10. What is a method of reducing hardness?

a. Softening

b. Hardening

c. Lightning

d. Flashing

11. The solid that adsorbs a contaminant is called the:

a. Adsorbent

b. Adsorbate

c. Sorbet

d. Rock

12. The adsorption process is used to remove:

a. Organics or inorganics

b. Bugs or salts

5.7 Chemical Feed Systems

159

c. Organisms or dirt

d. Color or particles

13. Describe two primary methods used to control taste and odor?

a. Oxidation and adsorption

b. Filtration and sedimentation

c. Mixing and coagulation

d. Sedimentation and clariﬁcation

14. What is the recommended loading rate for copper sulfate for algae control at an alkalinity

greater than 50mg/L ?

a. 0.9 of copper sulfate per acre of surface area

b. 1.9 of copper sulfate per acre of surface area

c. 2-4 lb of copper sulfate per acre of surface area

d. 5.4 of copper sulfate per acre of surface area

15. The basic goal for water treatment is to

a. Protect public health

b. Make it clear

c. Make it taste good

d. Get stuff out

16. Greensand can be operated in either

modes.

regeneration or

regeneration

a. Continuous or intermittent

b. Fast or slow

c. Hot or cold

d. Constant or unusual

Chapter 6

Disinfection . . . . . . . . . . . . . . . . . . . . . . . . 157

Background

6.1

6.2

6.3

6.4

6.5

6.6

Chlorination

Chlorine Dioxide

Ultraviolet (UV) disinfection

Ozone

Summary of Disinfectants’ Attributes

164

Chapter 6. Disinfection

6. Disinfection

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams

Ability to measure total chlorine

Ability to monitor and interpret chlorine residual

Knowledge of causes of chlorine demand

Knowledge of contact time

Knowledge of dechlorination techniques

Knowledge of the purpose of disinfection

Ability to apply disinfectant

Knowledge of water main disinfectant techniques

Knowledge of well disinfection techniques

Ability to choose the proper disinfectant technique

Ability to recognize when breakpoint has been met

Knowledge of advantages/disadvantages of chloramination

Knowledge of chloramine compounds

Knowledge of chlorine analysis techniques

Knowledge of disinfectant types and characteristics

Knowledge of factors affecting chlorine disinfection

Knowledge of the causes of DBPs

Knowledge of the chlorine curve

Knowledge of the deﬁnition of breakpoint chlorination

Ability to calculate chlorine/ammonia ratio for chloramination

Ability to calculate the surface area of the interior walls of a storage reservoir

Ability to calculate CT

Ability to recognize abnormal levels of DBPs in the water distribution system

Knowledge of chlorine chemistry

Knowledge of DBP compounds

Knowledge of DBP formation

Knowledge of DBP reduction methods

165

Expected Range of Knowledge for Water Properties and Sources

Water Treatment Operator License Exams

Knowledge of acceptable chlorine residual levels

Knowledge of breakpoint chlorination chemistry

Knowledge of chlorine chemistry

Knowledge of common chlorine compounds used for disinfection

Knowledge of disinfectant byproduct formation

Knowledge of disinfectant properties and uses

166

Chapter 6. Disinfection

6.1 Background

•

The primary goal of water treatment is to ensure that the water is safe to drink and does not

contain any disease-causing microorganisms.

Disinfection refers to an operation to inactivate the microorganisms in water that can cause

an infection or disease. These organisms are collectively referred to as pathogens and

include many species of bacteria, fungus, protozoa, worms, viruses, etc.

The processes prior to disinfection - sedimentation and ﬁltration, remove a large percent-

age of bacteria and other microorganisms from the water by physical means.

Disinfection is different from sterilization, which is the complete destruction of all organ-

isms which is expensive and unnecessary.

•

• Water disinfection can be sub-divided as:

1. Primary disinfection:

–

Kills or inactivates bacteria, viruses, and other potentially harmful organisms in

drinking water.

Disinfection prevents infectious diseases such as typhoid fever, hepatitis, and

cholera

Some disinfectants are more effective than others at inactivating certain poten-

tially harmful organisms.

Disinfection processes vary from water utility to water utility based on their

needs and to meet EPA treatment requirements.

2. Secondary disinfection:

–

Maintenance of a disinfectant residual that prevents regrowth of microorganisms

in the water distribution system between treatment and consumer.

Secondary disinfection maintains water quality by killing potentially harmful

organisms such as those that cause Legionnaire’s disease that may get in water

as it moves through pipes.

–

– Monochloramine is commonly used as a secondary disinfectant.

• Elements of an "ideal" disinfectant

– It must act in a reasonable time.

– It must act as temperature or pH changes.

– It must be nontoxic.

– No harmful byproducts.

– It must not add unpleasant taste or odor.

– It must be readily available.

– It must be safe and easy to handle and apply.

– It must be easy to determine the concentration of.

– It must be able to provide residual protection.

–

Pathogenic organisms must be more sensitive to the disinfectant than are nonpathogens.

– It must be capable of being applied continually.

6.2 Chlorination

167

– Versatile: effective against all types of pathogens.

– Fast-acting: effective within short contact times

–

Robust: effective in the presence of interfering materials including particulates, sus-

pended solids and other organic and inorganic constituents

Handy: easy to handle, generate, and apply (nontoxic, soluble, non-ﬂammable, non-

explosive)

–

– Compatible with various materials/surfaces in WTPs (pipes, equipments)

– Economical

•

In addition to the desirable characteristics of a disinfectant listed above, the disinfectant

chosen must be able to kill off or deactivate pathogenic microorganisms by one of several

possible methods, including:

1. Damaging the cell wall

2. Altering the ability to pass food and waste through the cell membrane

3. Altering the cell protoplasm

4. Inhibiting the cells’ conversion of food to energy

5. Inhibiting reproduction

•

Most chemical disinfectants being strong oxidizers, aid the water treatment process by

proding other beneﬁts which include:

– Taste and odor control

– Oxidize iron and manganese

– Limit nuisance growths - algae

– Reduce mudball formation in ﬁlter media

– Limit anaerobic sludge conditions

– Improving coagulation

6.2 Chlorination

• Despite potential drawbacks, chlorine is the disinfectant of choice.

•

In general, chlorination is effective, relatively inexpensive, and provides effective levels of

disinfectant residual for safe distribution.

• Chlorine can be applied as:

– As a gas - elemental chlorine, Cl₂:

– Liquid (sodium hypochlorite)

– Solid (calcium hypochlorite)

each of these forms has advantages and disadvantages.

6.2.1 Chlorine properties

• Chlorine is a yellowish-green gas at room temperature and atmosphric pressure

• Chlorine gas can be pressurized and cooled to its liquid form for making it easy to ship and

store.

168

Chapter 6. Disinfection

•

When liquid chlorine is released, it quickly turns into a gas that stays close to the ground

(being heavier than air) and spreads rapidly.

While it is not explosive or ﬂammable, as a liquid or gas it can react violently with many

substances

• Chlorine is only slightly soluble in water (0.3 to 0.7% by weight.)

• Chlorine gas has a greenish-yellow color

•

It has a characteristic disagreeable and pungent odor, similar to chlorine-based laundry

bleaches, and is detectable by smell at concentrations as low as 0.2 to 0.4 ppm

• It is about two and a half times as heavy as air

• One volume of liquid chlorine yields about 460 volumes of chlorine gas.

• Liquid chlorine is amber in color and is about one and a half times as heavy as water

• Chlorine is an irritant to the eyes, skin, mucous membranes, and the respiratory system

6.2.2 Chlorine storage and safety

•

Chlorine gas is lethal at concentrations as low as 0.1% air by volume. In nonlethal concen-

trations, it irritates the eyes, nasal membranes, and respiratory tract.

Typically for smaller plants chlorine gas is shipped in pressurized steel cylinders - 150 lb

or 2000 lb (ton cylinder) size. Larger plants may get their chlorine supply in rail tank cars.

The daily chlorine usage is typically established based upon the weighing of the chlorine

containers.

The withdrawal rates from a chlorine cylinder is based on the temperature of the liquid in

the cylinder, and thus the pressure of the gas.

• As chlorine gas is withdrawn from the cylinder, it absorbs the heat from the surroundings.

•

For low withdrawal rates, heat will be able to be transferred from the surrounding air to the

container in time so that there is no drop in temperature or pressure,

If the chlorine withdrawal is larger, the air will not be able to transfer the heat quickly

enough and the temperature (and pressure) of the chlorine will drop, thus resulting in a

lower feed rate.

•

If high enough and prolonged enough, this can even result in ice formation around the

outside of the container, further decreasing the withdrawal rate.

The most effective way to increase withdrawal rate from a single container is to circulate

the surrounding air with a fan. Again, never apply heat to the containers.

The maximum withdrawal rate for 100 or 150-pound cylinders should be limited to 40

pounds per day per cylinder. The maximum withdrawal rate for one-ton containers should

be limited to 400 pounds per day per cylinder.

•

If chlorine gas escapes from a container or system, being heavier than air, it will seek the

lowest level in the building or area

Only trained staff with access to proper personal protection equipment (PPE) including

self-contained breathing apparatus, should handle the chlorine cylinders and address chlo-

rine leak issues

6.2 Chlorination

169

•

When a leak is suspected, it is recommended that ammonia vapors be used to ﬁnd the

source. When ammonia vapor using a rag or brush, is directed at a leak, a white cloud will

form. To produce ammonia vapor, a plastic squeeze bottle containing about 5 % ammonia,

aqua ammonia (ammonium hydroxide solution) should be used. A weaker solution such as

household ammonia may not be concentrated enough to detect minor leaks

All safety equipment should be located outside of the chlorine room and be easily accessed

by all personnel

•

Small leaks around valve stems can usually be corrected by tightening the packing nut

or closing the valve. A leak can also be reduced by removing the chlorine as rapidly as

possible

•

If it cannot be added to the process there are several chemicals which can be used to ab-

sorb the chlorine gas. For example, chlorine can be absorbed by using 1 pounds of caus-

tic soda or hydrated lime, or 3 pounds of soda ash per pound of chlorine.

If the leaking container can be moved, it should be transported to an outdoors area where

minimal harm will occur. Keep the leaking part the most elevated so that gaseous chlorine

will leak rather than liquid chlorine.

If the leak is large, all persons in the adjacent area must be warned and evacuated. Only

authorized persons equipped with the proper breathing apparatus, and protective measures

to the eyes and body should investigate.

As water is not an efﬁcient absorbent for chlorine and the fact that chlorine reacts with

water to form very corrosive hydrochloric acid, never apply water to a leak or consider

submerging a chlorine cylinder (for example, in a pond or tank), since it will probably

ﬂoat.

• Remember to keep windward of the leak.

•

As chlorine cylinders pressure increases with temperature, as a safety measure the chlorine

cylinders are ﬁtted with fusible plug which melts between 158^oand 165^oF.

Keep chlorine cylinder or container emergency repair kits available. Be familiar with their

use and location.

Leaks at fusible plugs and cylinder valves requires special handling and emergency equip-

ment. The chlorine supplier must be notiﬁed immediately

Pin hole leaks in cylinder walls or ton tanks can usually be stopped by mechanical pres-

sure applications (clamps, turnbuckles, etc.). This only temporary and may require your

ingenuity.

• Leaking containers cannot be shipped.

• In general, daily inspection of all chlorine cylinders will avoid major problems

•

In order to respond to leaks in chlorine containers, kits speciﬁc to the size of the container

have been developed by the Chlorine Institute.

–

Emergency Kit "A" is designed for use with the standard 100 and 150 pound capacity

cylinders in chlorine service only. It contains devices and tools to contain leaks in

170

Chapter 6. Disinfection

and around the cylinder valve and in the side wall of chlorine cylinders.

–

Emergency Kit "B" is designed for use with the standard chlorine ton container. It

contains devices and tools to contain leaks in and around the ton container valves and

in the side wall of ton containers.

Emergency Kit "C" is designed for use with the standard chlorine tank car, chlorine

cargo tank and portable tank in chlorine service.

6.2.3 Forms of chlorine

Due to safety issues related to the use of chlorine gas, hypochlorites are often used in lieu

of chlorine

• Types of hypochlorites

•

–

Sodium hypochlorite (NaOCl) comes in a liquid form which contains up to 12.5%

chlorine

–

Calcium hypochlorite (Ca(OCl)₂), also known as High-test Hypochlorite (HTH), is a

solid which is mixed with water to form a hypochlorite solution. Calcium hypochlo-

rite is 65-70% concentrated.

•

Hypochlorites decompose in strength over time while in storage. Temperature, light,

and physical energy can all break down hypochlorites before they are able to react with

pathogens in water.

6.2.4 Chlorine reactions related to disinfection

Chlorine reacts with water to form hypochlorous and hydrochloric acids

Cl₂

H₂O

⇐⇒

HOCl

HCl

chlorine

water

hypochlorous acid hydrochloric acid

• Hypochlorous acid dissociates in water to form the hydrogen and hypochlorite ions

HOCl

⇐⇒

H⁺

OCl⁻

hypochlorous acid

hydrogen ion

hypochlorite ion

–

Hypochlorous acid is the most effective form of chlorine available to kill microorgan-

isms

– Hypochlorite ions is much less efﬁcient disinfectant

The concentration of hypochlorous acid and hypochlorite ions in chlorinated water will

depend on the water’s pH

•

–

A higher pH facilitates the formation of more hypochlorite ions and results in less

hypochlorous acid in the water

A signiﬁcant percentage of the chlorine is still in the form of hypochlorous acid even

between pH 8 and pH 9

6.2.5 Factors affecting chlorine disinfection

The disinfection efﬁciency of chlorine depends on the following factors:

6.2 Chlorination

171

•

pH: Disinfection is more efﬁcient at a low pH when large quantities of hypochlorous acid

are present than at a high pH when hypochlorite ions is the dominant species in the water

Concentration: Contact Time Ratio (CT): For effective chlorine disinfection both sufﬁcient

chlorine dosages – concentration (C) as well as contact time (T) are necessary. Generally

both of these factors must be worked out experimentally for a given system

Disinfection activity can be expressed as the product of disinfection concentration (C) and

contact time (T) - CT

•

• The same CT values will achieve the same amount of inactivation

•

Temperature: Colder temperatures are less favorable for disinfection. Proper contacting or

mixing or agitation: This is necessary to make sure that the chlorine applied contacts or

reaches the microbial cells

Organic and inorganic material present: The chlorine used by these organic and inorganic

reducing substances including metal ions, organic matter and ammonia, is deﬁned as the

chlorine demand. So that the amount of chlorine that has to be added to wastewater for

different purposes will also vary.

6.2.6 Chlorine Application

•

Continuous chlorination of systems less than 75 gpm is by the use of a hypochlorinator

where a motor driven pump pulls the hypochlorite solution out of a holding chamber and

pumps it into the water to be treated. Where the pipe from the pump joins the pipe carry-

ing the raw water, the Venturi effect creates a small vacuum and pulls the chlorine solution

into the water.

•

For larger system, chlorinators - devices which introduce chlorine gas to water using liquid

chlorine supplied in steel cylinders are used.

• In the commonly used Vacuum Chlorinator:

–

Chlorine gas is pulled from the cylinder into the source water by a vacuum created by

water ﬂowing through the injector and creating a negative head.

This negative head forces open the pressure regulating valve on the cylinder and

allows chlorine gas to ﬂow out of the cylinder and into the chlorinator.

Once the gas has entered the chlorinator, the chlorine feed rate is measured using an

indicator known as a rotameter

Just beyond the rotameter, the chlorine gas ﬂows past a regulating device (a V-notch

plug or a valve) which is used to adjust the chlorine feed rate.

6.2.7 Chlorination Byproducts

•

Main drawback of chlorine disinfection is the adverse health effects of the byproducts

- Disinfection by-products ( DBPs ) formed from its reaction with certain organic com-

pounds present in the water.

•

Adverse health effects on humans exposed to DBPs through drinking-water and oral, der-

mal, and inhalational contact with chlorinated water, include cancers of vital organs.

Halogenated trihalomethanes ( THMs ) and haloacetic acids ( HAAs ) are two major

172

Chapter 6. Disinfection

Figure 6.1: Vacuum Chlorinator

classes of disinfection byproducts (DBPs) commonly found in waters disinfected with

chlorine.

•

At the present time, about 90% of U.S. water utilities use chlorine to disinfect water. Al-

though chlorine has virtually eliminated the risks of waterborne disease such as typhoid

fever, cholera, and dysentery, recent studies have shown risks associated with byproducts

of chlorine—a reason why water utilities already have been looking at alternative methods

for disinfecting water.

• Approaches for reducing DBPs includes:

–

Avoiding pre-chlorination where chlorine is added to the raw water before coagula-

tion and ﬁltration.

– Removal of organics using Aeration or adsorption on activated carbon

–

reevaluating the chlorine dosing to a level which will accomplish the same degree of

disinfection with a lower chlorine dosage.

– Another current approach is using alternative disinfection methods.

6.2.8 Chloroamination

•

When chlorine is added to water containing ammonia, chlorine reacts with ammonia to

form chloramines.

Water utilities practice chloroamination - practice of utilizing the disinfectant properties of

chloramines, by feeding chlorine to the water containing ammonia.

Chloramines are not as reactive as chlorine and are not as effective as chlorine as primary

oxidizers. However, chloramines decay rate is much slower than that for chlorine.

Chloramine is used as a secondary disinfectant to maintain a disinfectant residual through-

out the distribution system so that drinking water remains safe as it travels from the treat-

ment facility to the customer.

•

One-third of all public water systems in the United States use chloramine for residual

disinfection.

Chloramines are formed by the controlled addition of ammonia to chlorinated water form

6.2 Chlorination

173

monochloramine (NH₂Cl), often in the recommended chlorine to ammonia ratio of 4.5:1 to

prevent nitriﬁcation.

NH₃+ HOCl NH₂Cl + H₂O

•

Chlorine reacts with ammonia as follows: When chlorine is added to water containing

ammonia:

1. First the free chlorine in contact with ammonia forms monochloramine and water

NH₃+HOCl → NH₂Cl(monochloramine)+H2O

– Monochloramine has disinfection properties

– Dominates when Cl:N mass ratio is 0 to 5:1

2. Monochloramine reacts further with chlorine to give dichloramine and water

HOCl +NH₂Cl → NHCl₂+H₂O

Also, monochloramine auto decomposes into dichloramine

2NH₂Cl → NHCl₂+NH₃

– Dichloramine is formed between 5:1 and 7:1 Cl:N mass ratio

–

Dichloramine is a more effective disinfectant than monochloramine but their

use may cause taste and odor problems. Thus the water industry only uses

monochloramine as a disinfectant.

NH₂Cl +HOCl → NHCl₂(dichloramine)

at pH 7.5, monochloramine is the dominant chloramine species as pH decreases

from 7.5, dichloramine becomes the dominant chloramine species increases in the

chlorine to nitrogen dose ratio results in corresponding increases of nitrogen trichlo-

ride, but only when the pH is < 7.4

3. Formation of nitrogen trichloride from the reaction of chlorine and dichloramine

does not typically occur as it is the favored product at low pH - <4

NHCl₂+HOCl → NCl₃(nitrogentrichloride)

4. Additional free chlorine +chloramines → H⁺+H2O+N₂

Chloramine levels up to 4 milligrams per liter (mg/L) or 4 parts per million (ppm) are

considered safe in drinking water. At these levels, harmful health effects are unlikely to

occur.

•

Chloramines have disinfection properties albeit much lower than free chlorine ( 5% of free

available chlorine) but last much longer in the system than free chlorine.

Monochloramine is about 2,000 and 100,000 times less effective than free chlorine for the

inactivation of E. Coli and rotaviruses, respectively.

6.2.9 Advantages of Chloramines

•

As chloramines do not tend to react with organic compounds, its use can reduce the forma-

tion of cancer-causing disinfection byproducts, such as the trihalomethanes and haloacetic

acids and also result in fewer taste and odor complaints.

•

Chloramine being more stable, its residual and thus its disinfectant beneﬁt can persist for

several days.

174

Chapter 6. Disinfection

•

Chloramine dosing systems are relatively easy to install and operate. It also is among the

less expensive disinfectant alternatives to chlorine.

6.2.10 Disadvantages of Chloramines

• Poorest Disinfection

• No taste and odor control or other aesthetic quality beneﬁts.

•

Chloramine levels are more difﬁcult to regulate than chlorine levels. Too much free ammo-

nia remaining in the distribution system can lead to nitriﬁcation and increased corrosion of

pipes in the distribution system.

6.2.11 Breakpoint Chlorination

Breakpoint chlorination curve provides a graphical representation of the fate of chlorine as it

is being added to water containing ammonia and serves as an important tool for systems using

chloramination, The breakpoint curve can be explained as follows:

• Point A is at the beginning of chlorine application

•

Between Points A and B, the chlorine dosage produces no residual because of an immedi-

ate chlorine demand caused by fast-reacting ions from metal salts and H₂S.

• Point B is the beginning of the reaction between chlorine and ammonia present

• Mono and dichloramines are formed between points B and C

6.2 Chlorination

175

•

Zone 1 - between points A and C, is the combined zone and has mono and di chloramines

and ammonia. Mono chloramines is a stable disinfectant while dichloramines is a strong

disinfectant but unstable.

•

After the maximum combined residual is reached (point C), further chlorine doses de-

crease the residual due to chloramine oxidation to dichloramine, occurring between points

C and D. This is Zone 2 - Breakpoint Zone

•

Point D represents the breakpoint - the point at which chlorine demand has been satisﬁed

and additional chlorine appears as free residuals

Between points D and E, free available residual chlorine increases in direct proportion

to the amount of chlorine applied. This is Zone 3 which is the free chlorine zone and has

hypochlorous acid but no ammonia.

•

Breakpoint chlorination is the application of sufﬁcient chlorine beyond the chlorine de-

mand to maintain a free available chlorine residual.

Theoretically chlorine requirement = Wt. NH₃-N x 7.6

In practice (Margin of safety) = Wt. NH₃-N x 10

•

After the breakpoint, free chlorine residuals develop. Free chlorine residuals usually de-

stroy odors, kill microorganisms and oxidize organic matter.

Factors that affect breakpoint chlorination are initial ammonia nitrogen concentration, pH,

temperature, and demand exerted by other inorganic and organic species

Weight ratio of chlorine applied to initial ammonia nitrogen must be 8:1 or greater for the

breakpoint to be reached. If the weight ratio is less than 8:1, there is insufﬁcient chlorine

present to oxidize the chlorinated nitrogen compounds initially formed

When instantaneous chlorine residuals are required, the chlorine needed to provide free

available chlorine residuals may be 20 or more times the quantity of ammonia present.

Reaction rates are fastest at pH 7-8 and high temperatures

•

6.2.12 Chlorine dosing terms

•

Chlorine dose - the amount of chlorine added to the system. It can be determined by

adding the desired residual for the ﬁnished water to the chlorine demand of the untreated

water. Dosage can be either milligrams per liter (mg/L) or pounds per day (lb/day).

Chlorine Demand - the amount of chlorine consumed by iron, manganese, turbidity,

algae, and microorganisms in the water. Because the reaction between chlorine and mi-

croorganisms is not instantaneous, demand is relative to time. For instance, the demand 5

minutes after applying chlorine will be less than the demand after 20 minutes.

Free chlorine - free chlorine refers to all chlorine present in the water as Cl₂(g), HOCl(aq)

and OCl⁻(aq).

•

Combined residual - is the result of combining free chlorine with nitrogen compounds.

Combined residuals are also referred to as chloramines.

Total chlorine residual - is the mathematical combination of free chlorine and combined

residuals. Total residual can be determined directly with standard chlorine residual test

176

Chapter 6. Disinfection

kits. Residual, like demand, is based on time. The longer the time after dosage, the lower

the residual will be, until all of the demand has been satisﬁed. Residual, like demand,

is expressed in mg/L. The presence of a free residual usually provides a high degree of

assurance that the disinfection of the water is complete.

ChlorineDose(mg/L) = ChlorineDemand+ChlorineResidual

•

Theoretically, while microorganisms are killed as the chlorine demand is being satisﬁed,

disinfection is generally the result of chlorine residual or the amount of chlorine remaining

after the chlorine demand has been satisﬁed.

6.2.13 Contact Time

•

Contact time is the amount of time which the chlorine has to react with the microorgan-

isms in the water, which will equal the time between the moment when chlorine is added

to the water and the moment when that water is used by the customer.

The longer the contact time, the more efﬁcient the disinfection process is. When using

chlorine for disinfection a minimum contact time of 30 minutes is required for adequate

disinfection.

•

Contact time is just as important as the chlorine residual in determining the efﬁciency of

chlorination.

An operator measures the amount of contact time available at the plant before the water

goes out to the public to ensure that 99.9% of giardia lamblia is either removed with ﬁltra-

tion or inactivated with chlorine before the water gets to the public.

• The operator compares the contact time at the plant to the CT tables provided by the EPA.

•

As long as the contact time the operator measures at the plant is greater than that required

by the EPA, the water passes the disinfection portion of the treatment process.

The "bafﬂing efﬁciency" of a tank is used to determine chlorine contact time in the tank.

If the water used to calculate disinfection contact time moves through a storage tank, pres-

sure tank, or pipes too quickly, the situation is called "shortcircuiting".

•

Some vessels provide better contact time than others do. Water systems can modify reser-

voirs to improve the bafﬂing efﬁciency.

In some cases little or no bafﬂing efﬁciency can be awarded. Pipes with a length to width

ratio of 150 or more typically have a bafﬂing efﬁciency of 100 percent.

Table below provides theoretical bafﬂing factors for various bafﬂing conditions and factors.

In summary, to calculate CT you must know:

1. The contact time (T) for each water system component between the chlorine injection

point and where free chlorine is measured before the ﬁrst customer.

2. The volume and bafﬂing efﬁciency of each component.

3. The peak ﬂow through each component.

6.2 Chlorination

177

Table 6.1: Theoretical Bafﬂing Factors

4. The free chlorine residual measured downstream of all the components and upstream of

the ﬁrst customer.

When calculating Contact Time, use the lowest volume of water in the tank under non-emergency/normal

operating conditions.

The following steps have been set up to help operators determine contact time.

Step 1: Determine the time available in the basin at peak ﬂow. Multiply the basin volume by the

bafﬂing factor and divide by the Peak Hourly Flow to determine the Time portion of the contact

time equation.

Basin Volume ( gal )x bafﬂing factor

Time (min) =

Peak Hourly Flow (gpm)

Step 2: Determine the contact time available at peak ﬂow. Multiply the Time by your chlorine

concentration at peak hourly ﬂow. This is the Contact Time you have available.

Available Contact Time (minmg/L) = Time (min)× Chlorine concentration (mg/L)

Step 3: Find the required Contact Time (CT) from the tables at peak ﬂow. Determine the CT

required by the EPA. You need to do this by looking up the CT from the CT tables provided

using your pH, temperature and chlorine concentration.

Step 4: Does your water system meet CT requirements?

Compute the inactivation ratio by dividing the actual contact time by required contact time. If the

rateo is greater than 1 , then your water system met its contact time requirements. If you cannot

meet contact time, you can either increase your storage volume or increase your disinfectant

residual.

Actual Contact Time

Required Contact Time

Inactivation Ratio =

Example: Your campground has a 5,000 gallon steel tank. An engineer has determined that

the bafﬂing factor for the tank is 0.3. The ﬂow of water through the system is determined to

be 15 gallons per minute at maximum ﬂow conditions. The pH is 7.0 and the temperature is

10 Celsius. Determine whether or not your campground meets contact time requirements at

1.5mg/L chlorine.

178

Chapter 6. Disinfection

Step 1:

5,000gal×0.3

Time (min) =

15gpm

Time (min) = 100

Step 2: Available Contact Time ( minmg/L) = Time (min)× Chlorine concentration (mg/L)

Available Contact Time (minmg/L) = 100 min×1.5mg/L

Available Contact Time (minmg/L) = 150

Step 3: Look up the contact time that you need to achieve from the applicable EPA CT Table -

Chlorine disinfectant, pH=7.0, 1.5 mg/l chlorine residual and temperature=10^oC

Figure 6.2: EPA - CT Table

You will notice under the Chlorine Concentration (mg/L) column, 1.5mg/L is not listed, so use

the next lowest chlorine residual, 1.4mg/L. Look at the table at 1.4mg/L and go across to the

pH = 7.0. The CT required for compliance, from the table, is 58 mg/l-min.

Step 4: Is the inactivation ratio greater than 1 ? Divide 150 by 58 to get 2.6. Since 2.6 is greater

than 1 your system did meet the contact time requirements.

150

Inactivation Raio =

Inactivation Raio = 2.6

6.3 Chlorine Dioxide

•

Chlorine dioxide, a greenish-yellow gas, produced by reacting sodium chlorite with chlo-

rine or an acid.

•

Because it is explosive under pressure and difﬁcult to transport, it is generated on-site by

reacting chlorite with chlorine or hydrochloric acid.

• Chlorine dioxide is a strong disinfectant.

6.4 Ultraviolet (UV) disinfection

179

• The efﬁciency is pH dependent; is is optimum at a pH of 3 to 5.

6.3.1 Advantages of Chlorine Dioxide

• Chlorine dioxide has a higher oxidation capacity than most species of chlorine.

• It does not hydrolyze to form an acid, and therefore is less corrosive.

•

Unlike chlorine, it acts only by oxidation and does not combine with organic compounds

to form environmentally hazardous disinfection by-products.

• Its effectiveness is not affected by ammonia and pH, and does not produce THMs.

• Its effectiveness against Giardia and Cryptosporidium is reported as better than chlorine.

6.3.2 Disdvantages of Chlorine Dioxide

Chlorine dioxide is unstable and reverts to chlorite and therefore it needs to be generated at

•

the site and applied immediately.

• It is relatively expensive to generate

• It is explosive at a concentration above 10 percent in the air.

• It forms chlorites and chlorates which cause an anemic condition in some individuals.

6.4 Ultraviolet (UV) disinfection

•

UV Disinfection of wastewater is conducted in specially designed reactors ﬁtted with

ultraviolet lamps producing energy in the UV-C range (200-400 nm)

The UV lamps produce light photons that attack the microorganisms in wastewater as it

ﬂows through the reactor.

Within only a few seconds of exposure to the UV energy, the DNA of the microorganisms

is permanently altered and the bacteria can no longer reproduce or infect those coming in

contact with the water.

• UV for wastewater disinfection has been in use for more than 50 years

•

Increased interest after the discovery in the late 1990’s of its remarkable effectiveness

against Cryptosporidium parvum and Giardia lamblia - pathogens in surface waters which

can ﬁnd its way into the drinking water supplies

•

The big advantage of UV disinfection over chlorine and ozone is that UV does not involve

chemical use.

µW−sec

mJ−sec

The UV dose expressed as

is the product of UV intensity (energy per unit

cm²

surface area) - mJ/cm²or µW/cm²and residence time - sec.

6.4.1 Advantages of UV disinfection

• Very effective against bacteria, fungi, protozoa

• Independent on pH, temperature, and other materials in water

• Smaller reactor size requirement compared to chlorination

180

Chapter 6. Disinfection

6.4.2 Disadvantages of UV disinfection

•

Suspended solids, slime growth, turbidity, and color present in wastewater will inhibit the

effectiveness of UV

• No lasting residuals

•

UV light tends to ionize compounds and break them apart (i.e. nitrate could become nitrite

in UV light), causing toxic effects on the efﬂuent.

• Expensive

6.5 Ozone

• Ozone (O₃) is the triatomic form of oxygen - it is composed of three oxygen atoms.

•

Under normal conditions ozone is unstable and quickly decomposes to the more stable

gaseous oxygen, O₂.

Because of its instability, ozone cannot be stored and thus generated at the point of applica-

tion.

Ozone is generated by passing air or oxygen through an electrical discharge - the notice-

able clean smell in the air after a thunder and lightning storm is likely due to the formation

of ozone due to the lightning bolts passing through the atmosphere.

• Ozone is thirteen times more soluble in water than oxygen.

• Ozone is even more effective against some viruses and cysts than chlorine.

•

It has the added advantage of leaving no taste or odor and is unaffected by pH or the am-

monia content of the water.

•

When ozone reacts with reduced inorganic compounds and with organic material, an oxy-

gen atom instead of a chloride atom is added to the organics, the end result being an envi-

ronmentally acceptable compound.

•

Ozone disinfects 3,100 times faster than chlorine. It has also been found that disinfection

occurs within contact times of 3 to 8 seconds.

• Viricidal properties of ozone is exhibited at longer contact time of about 5 minutes needed.

•

Any residual ozone in the efﬂuent of the contactor disappears in a matter of seconds out-

side the contactor.

6.5.1 Advantages of ozonation

The advantages of ozonation include :

• Reduces colors, phenolics, cyanides, oxygen demanding matter, turbidity and surfactants

• Increases dissolved oxygen

• Does not produce any signiﬁcant toxic by-products

• Increases suspended solids reduction

6.5.2 Disadvantages of ozonation

The disadvantages of ozonation include :

6.6 Summary of Disinfectants’ Attributes

181

• High capital cost

• High electric consumption

• Highly corrosive, especially with steel or iron and even oxidizes Neoprene

• Ozone promotes formation of bromates and brominated DBPs.

6.6 Summary of Disinfectants’ Attributes

➼ Pathogen Destruction: Ozone > ClO₂> Chlorine » Chloramines

➼ Residual Stability: Chloramines > Chlorine > > ClO₂> Ozone

➼ Other Treatment Beneﬁts: Chlorine > Ozone, & ClO₂» Chloramines

➼ Disinfection By-Product Yield: Chloramines » ClO₂Ozone & Chlorine

Chapter 6 Assessment

1. The two most common types of chlorine disinfection by-products include:

a. TTHM and HAA5

b. TTHA of HMM5

c. Turbidity and color

d. Chloride and ﬂuoride

2. Chlorine gas is times heavier than breathing air

a. 2.5

b. 20

c. 60

d. 460

3. A commonly used method to test for chlorine residual in water is called the method.

a. HTH

b. THM

c. VOC

d. DPD

4. When chlorine gas is added to water the pH goes down due to

a. chlorine gas producing caustic substances

b. two base materials that form

c. two acids that form

d. caustic soda being formed in the water

5. Disinfection by-products are a product of:

184

Chapter 6. Disinfection

a. Filtration

b. Disinfection

c. Sedimentation

d. Adsorption

6. Chloramine is most effective as a disinfectant.

a. Primary

b. Secondary

c. Third

d. First

7. Name two methods commonly used to disinfect drinking water other than chlorination.

a. Ozone and ultraviolet light

b. Soap and agitation

c. Filtration and adsorption

d. Salt and vinegar

8. In order to determine the effectiveness of disinfection, it is desirable to maintain a disinfec-

tant residual of at least mg/L entering the distribution system.

a. 0.10

b. 0.5

c. 0.3

d. 0.2

9. Secondary disinfectants are used to provide a in the distribution system.

a. Color

b. Chemical

c. Smell

d. Residual

10. Primary disinfectants are used to microorganisms.

a. Hurt

b. Inactivate

c. Burn up

d. Evaporate

11. The quantity of chlorine remaining after primary disinfection is called a residual.

a. Chlorine

b. Permaganate

c. Hot

d. Cold

12. The two most common types of chlorine disinfection by-products include:

a. TTHM and HAA5

b. TTHA of HMM5

c. Turbidity and color

d. Chloride and ﬂuoride

6.6 Summary of Disinfectants’ Attributes

185

13. In order to determine the effectiveness of disinfection, it is desirable to maintain a disinfec-

tant residual of at least mg/L entering the distribution system.

a. 0.10

b. 0.5

c. 0.3

d. 0.2

14. A

a. Large

residual of chlorine is required throughout the distribution system.

b. High

c. Trace

d. Hot

15. The test used to determine the effectiveness of disinfection is called the:

a. Coliform bacteria test

b. Color test

c. Turbidity test

d. Particle test

16. Name two methods commonly used to disinfect drinking water other than chlorination.

a. Ozone and ultraviolet light

b. Soap and agitation

c. Filtration and adsorption

d. Salt and vinegar

17. Name the two types of hypochlorites used to disinfect water.

a. Chloride and monochloride

b. Sodium and calcium

c. Ozone and hydroxide

d. Arsenic and manganese

18. Free chlorine can only be obtained after

chlorination has been achieved.

a. Breakpoint

b. Fastpoint

c. Softpoint

d. Onpoint

19. The meaning of the " C" and the " T " in the term CT stands for:

a. Concentration and time

b. Color and turbidity

c. Calcium and tortellini

d. Chlorine and turbidity

20. Chloramine is most affective as a disinfectant.

a. Primary

b. Secondary

c. Third

186

Chapter 6. Disinfection

d. First

21. TTHMs and HAA5s can affect:

a. Health

b. Aesthetics

c. Color

d. Odor

Chapter 7

VII

Pumping Systems . . . . . . . . . . . . . . . . . . . 183

Background

7.1

7.2

7.3

7.4

Rotodynamic Pumps

Positive Displacement Pump

Pump Calculations

7. Pumping Systems

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams

Ability to read and interpret a pressure gauge

Ability to recognize abnormal pressure readings (too high or too low)

Ability to recognize abnormal pump operating conditions

Knowledge of pump types

Knowledge of the causes of water hammer

Knowledge of the deﬁnition of water hammer

Knowledge of the relationship between water velocity and water pressure

Knowledge of water hammer reduction techniques

Ability to recognize the signs of cavitation

Ability to repair and replace pump and motor system components

Knowledge of operational principles of a water pump

Knowledge of packing gland settings

Knowledge of pump maintenance procedures

Knowledge of the causes of cavitation

Knowledge of the mechanical components of pumps and motors

Knowledge of the relationship between head loss and friction

Ability to interpret a pump curve

Ability to match pump type to application

Knowledge of proper phase balance

190

Chapter 7. Pumping Systems

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams (Continued)

Knowledge of proper pump alignment

Knowledge of recordkeeping requirements

Knowledge of the effect of corrosion on head loss

Knowledge of when to "MEG" a motor

Water Treatment Operator License Exams (Continued)

Ability to discriminate between normal and abnormal operation of a water pump

Knowledge of pump types and uses

Knowledge of the components of a water pump

Knowledge of the operation of a water pump

Knowledge of valve types and uses

Ability to replace components of a water pump

Knowledge of pump installation procedures

Ability to administer a safety plan

7.1 Background

191

7.1 Background

•

A pump is a device that inputs energy into the water to increase its pressure and/or increase

its ﬂow. Pumps typically convert electrical energy into hydraulic energy of the water.

For water treatment and distribution, pumps are widely used for purposes which include

the following:

–

Remove water from a source, such as a river, lake, reservoir, well, spring, or muskeg

pond.

– Move water from the treatment plant to the distribution system or reservoir.

– Circulate water through a distribution system.

– Maintain pressure in the distribution system.

– Pump chemicals into the system.

Figure 7.1: Pump Types

• Pumps can be classiﬁed as:

1. Rotodynamic pumps: Here the energy is continuously imparted to the pumped ﬂuid

by means of a rotating impeller, propeller or rotor.

These pumps transfer mechanical energy to the ﬂuid primarily by increasing the ﬂuid

kinetic energy. Kinetic energy is then converted into potential energy (pressure) in

the discharge collector.

The most common types of rotodynamic pumps are:

– Radial (centrifugal)

– Mixed ﬂow, and

– Axial ﬂow (propeller) pumps - vertical turbine pumps.

192

Chapter 7. Pumping Systems

Figure 7.2: Types of Rotodynamic Pumps

2. Positive-displacement pump: These pumps utilize a mechanical device such as a

piston or plunger to pump the ﬂuid.

7.2 Rotodynamic Pumps

With this pump, the volume of the liquid delivered for each cycle depends on the resistance

offered to ﬂow. A pump produces a force on the liquid that is constant for each particular speed

of the pump. Resistance in a discharge line produces a force in the opposite direction. When

these forces are equal, a liquid is in a state of equilibrium and does not ﬂow. If the outlet of a

non-positive-displacement pump is completely closed, the discharge pressure will rise to the

maximum for a pump operating at a maximum speed.

7.2.1 Centrifugal pumps

• Centrifugal pumps are the most common type of pump used in water systems.

•

In a centrifugal pump, energy is transferred from the shaft to the impeller and from the

impeller to the water.

•

Centrifugal force - the force used to throw the water from the spinning impeller in a cen-

trifugal pump, is the same force that is experienced by the ball when whirled on a string.

• The centrifugal pump components related to imparting the energy to the water include:

–

Volute - Also called casing, it surrounds the impeller. Its spiral-like geometry with

an increasing through-ﬂow area, reduces the impeller induced ﬂuid velocity and

increases its static pressure. The ﬂuid exiting the casing is then diffused towards the

casing discharge.

–

Impeller - A rotating set of vanes designed to impart rotation to a mass of ﬂuid. ﬂow

enters the impeller which is in line with the pump shaft but the ﬂow exits from the

impeller perpendicular to the pump shaft.

Water being pumped provides cooling to dissipate the heat generated by its moving

parts - shaft and impeller. If the pump is run dry for an extended period of time, the

heat generated may severely damage to the pump and greatly limiting its service life.

7.2 Rotodynamic Pumps

193

Centrifugal Pump Operating Principle

Centrifugal Pump Types

1. One way to classify impellers is based on the use a or lack of shroud or covering.

•

Closed impeller: This impeller has a top and bottom shroud and is used in large

pumps primarily in clean water pumping application as it is prone to clogging when

in contact with solids.

Open impeller: Here the vanes are open on both sides. Without the shroud support

the vanes are weaker and are used in inexpensive pumps for applications without

much strain.

Semi-open impeller: These impellers have a back wall which adds mechanical

strength to the vanes. These impellers are suited for medium sized pumps with a

small amounts of soft solids.

Figure 7.3: Impeller Types

2. Classiﬁcation of centrifugal pumps based upon the conﬁguration of the suction - point of

entry of the into the pump:

•

End-suction centrifugal pumps - The most common style of centrifugal pump. The

center of the suction line is centered on the impeller eye. End suction centrifugal

pumps are further classiﬁed as either frame-mounted or close-coupled.

End-suction centrifugal can be classiﬁed

–

Frame mounted: These pumps are mounted next to a motor on a common base-

194

Chapter 7. Pumping Systems

plate, with the pump shaft and the motor shaft connected by a ﬂexible coupling.

The design includes a bearing housing to prolong the life of the bearings and

allows for continuous operation with high radial and thrust loads.

Frame-mounted pumps are commonly used for larger applications, where power

ratings are anywhere from 20HP to 200HP plus.

–

Close-coupled: A close-coupled pump has only one shaft and one set of bear-

ings: the motor shaft and bearings. The pump impeller is placed directly onto

the motor shaft. Close-coupled pumps require less space and are less expensive

than frame-mounted pumps.

Frame Mounted End-Suction Pump

Close-Coupled Pump

• Split-case centrifugal pumps:

– A centrifugal pump designed so that the volute case is split horizontally.

– The case divides on a plane that cuts though the eye of the impeller.

– This design allows easy access to the pump’s internal parts for maintenance.

–

Split-case pumps are used in high ﬂow applications including water treatment

plants for distributing potable water and for ﬁre protection.

– Split-case pumps are classied based upon their case design:

Radial Split – Radially split pump casing opens perpendicular to the shaft

axis and parallel to the impeller.

Axial Split – In this design, the pump casing is spliced into two halves that

get separated horizontally, or you can say that parallel to the shaft axis.

Figure 7.4: Horizontal Split-case pumps Radial and Axial

7.3 Positive Displacement Pump

7.2.2 Axial-ﬂow Pumps

195

Figure 7.5: Axial ﬂow pump

• Utilizes a propeller driven by a sealed motor in a pipe to impart the hydraulic energy.

• Unlike the centrifugal pumps, the direction of ﬂow is unchanged in axial-ﬂow pumps.

• The axial ﬂow

•

Axial ﬂow pumps are characterized by the highest ﬂow rates and lowest discharge pres-

sures. Vertical turbine pump - These type of centrifugal pumps are primarily mounted with

a vertical shaft; the motor is commonly mounted above the pump. Vertical turbine pumps

are either mixed or axial ﬂow devices.

7.2.3 Mixed-ﬂow Pumps

• Mixed ﬂow pumps borrow design characteristics from both axial and radial pumps.

•

Their design includes a diagonally operating impeller that uses centrifugal force to direct

the water out of the pump and give it an axial pushing action.

This dual pumping action enables mixed ﬂow pumps to have higher mass ﬂow rate of axial

pumps with higher pressure of centrifugal pumps.

Therefore, mixed ﬂow pumps are ideal for any application that requires the pumps to

operate within the gap left between axial and radial pumps.

7.3 Positive Displacement Pump

•

A positive displacement pump operate by forcing a ﬁxed volume of ﬂuid from inlet pres-

sure section of the pump into the discharge zone of the pump.

Positive displacement pumps are a category of pumps designed to move ﬂuid at a steady

rate through a system.

These pumps are able to handle viscous ﬂuids, which ﬂow at lower speeds and create more

resistance, more efﬁciently than kinetic (dynamic) pumps.

• These pumps cannot achieve high ﬂow rates and are typically used not for pumping water.

•

They are used typically for chemical dosing applications including dosing coagulants

and ﬂocculants as they are more efﬁcient in applications involving low ﬂows of higher

viscosity ﬂuid.

• Displacement pumps will not change their volume with a change in discharge pressure.

196

Chapter 7. Pumping Systems

• It can be classiﬁed into two types:

1. Rotary-type positive displacement pump:

–

This pump can move the ﬂuid by using a rotating mechanism that creates a

vacuum that captures and draws in the liquid.

– Rotary positive displacement pump can be classiﬁed into two main types:

Gear Pump:

Figure 7.6: Gear Pumps

This pump provides a constant volume of ﬂuid that passes between the

teeth of two meshing gears and the casing.

The rotating gears and separation of teeth create a suction that pulls ﬂuid

in through the inlet.

The gears then trap the liquid and move it around the casing to the dis-

charge or outlet.

· Each revolution creates consistency in the ﬂow of ﬂuid.

There are two main types of rotary gear pumps - internal and external

which are differentiated by the way the gear teeth lock together.

Lobe pump:

Figure 7.7: Lobe Pump

Lobe pumps are like gear pumps in that ﬂuid ﬂows around the interior of

the casing, but they use lobes instead of the gears with teeth.

The lobes do not touch each other, thus reducing wear, and they are driven

by external timing gear which can allow the lobe pump to operate in

either direction.

Rotary lobe pumps are capable of handling thick ﬂuids that are laden

with solids. Their gentle handling of solids works well mixed with low

7.3 Positive Displacement Pump

197

viscosity substances.

Screw pump:

Figure 7.8: Screw pump - Twin-screw type

Screw pumps and twin-screw pumps use rotating screws to move liquids

and solids from one end of the pump to the other.

· The turning action creates a spinning motion that pumps material.

The twin-screw pumps are identical to the screw pump, but with a dual

screw for more power.

Screw pumps are capable of high ﬂow rates with very little to no vibra-

tion.

2. Reciprocating-type positive displacement pump:

–

This pump works by the repeated back-and-forth movement (strokes) of either a

piston, plunger or diaphragm.

– Types of this pump are:

Piston pump: In a piston pump, the ﬁrst stroke of the piston creates a vac-

uum, opens an inlet valve, closes the outlet valve and draws ﬂuid into the

piston chamber (the suction phase). As the motion of the piston reverses,

the inlet valve, now under pressure, is closed and the outlet valve opens

allowing the ﬂuid contained in the piston chamber to be discharged (the

compression phase).

Plunger pump: The plunger pump works similar to the piston pump. The

volume of ﬂuid moved by a piston pump depends on the cylinder volume; in

a plunger pump it depends on the plunger size.

Diaphragm Pump: A diaphragm pump uses a ﬂexible membrane instead

of a piston or plunger to move ﬂuid. By expanding the diaphragm, the vol-

ume of the pumping chamber is increased and ﬂuid is drawn into the pump.

Compressing the diaphragm decreases the volume and expels some ﬂuid.

Diaphragm pumps have the advantage of being hermetically sealed systems

making them ideal for pumping hazardous ﬂuids.

–

The cyclic action of reciprocating pumps creates pulses in the discharge with

the ﬂuid accelerating during compression and slowing down during the suction

198

Chapter 7. Pumping Systems

Figure 7.9: Reciprocating Pumps Design

phase.

–

Pulsing can be minimized by using two or more pistons, plungers or diaphragms

with on in its compression phase whilst the other is in suction.

The repeatable and predictable action of reciprocating pumps make them ideal

for applications where accurate metering or dosing is required.

7.3.1 Turbine Pumps

•

Turbine pumps are centrifugal in nature but have some characteristics of positive displace-

ment.

•

First, the way they impart energy to the liquid is kinetic (and hence centrifugal) in nature.

However, they typically have multiple “stages,” with each stage generating a little incre-

mental pressure. Since each stage is incremental, the risk of cavitation is lower.

Clearances are said to be very tight, and hence, the reference to them having some charac-

teristics of positive displacement pumps.

•

They are often used in high head but relatively low-volume applications, such as pumping

water a signiﬁcant height. Typical applications include wells that are bored to provide

agricultural or turf irrigation, or to provide water supply for municipalities that rely on

ground water rather than surface water. They are also used to provide plant make-up water

and ﬁre water for industrial plants.

•

Mostly due to their compact size and multiple stage capability, their typical application

7.3 Positive Displacement Pump

199

is with clean water (fresh or waste) with minimal solids content. (Their relatively close

tolerances cannot long survive abrasive slurries such as drilling muds.)

The term “turbine” in the pump name is somewhat of a misnomer, as this pump type has

nothing to do with a turbine.

•

The pump end consists of at least one rotating impeller that is attached to a shaft and di-

rects the well water into a diffuser casing called a bowl.

This pump is often staged – that is, designed with more than one impeller. Each additional

impeller increases the amount of head the pump can produce while the ﬂow remains un-

changed.

•

In a staged turbine pump, water enters the pump at the bottom through a bell-shaped part

called the suction bell. From there it moves into the ﬁrst stage impeller, which raises the

water’s velocity. The water then enters the diffuser bowl immediately above the impeller,

where this high velocity energy is converted into high pressure. The bowl also directs the

ﬂuid into the next impeller located immediately above the bowl, and this process continues

through all of the stages of the pump.

•

The two main types of turbine pumps are vertical turbine pumps and submersible turbine

pumps.

While submersible pumps have the electric motor located underwater at the bottom of the

pump, vertical turbine pumps have the motor located above ground, connected via a long

vertical shaft to impellers at the bottom of the pump.

Figure 7.10: Turbine Pumps

7.3.2 Choosing Between Positive Displacement and Centrifugal Pumps

• Common Positive Displacement Pump Applications and Handled Fluids:

– High-viscosity ﬂuids (e.g., chemicals including polymers)

– High-pressure requirements

200

Chapter 7. Pumping Systems

– Low ﬂow rate requirements

• Common Centrifugal Pump Applications and Handled Fluids:

– Most water pumping applications

– High-ﬂow applications

7.3.3 Mechanical Parts of Rotodynamic Pumps

Figure 7.11: Centrifugal Pump Components

The mechanical parts of a typical rotodynamic pump include:

• Wear Rings:

With closed impellers, the impeller ﬁts very close to the case. As a result, the case is worn

by material passing from the high-pressure side to the low-pressure side of the impeller. To

protect the case, brass or stainless steel wear rings are inserted into the case which creates

the contact area between rotating and stationary parts inside the pump.

• Volute Case:

Around the impeller is the volute case. The volute case gathers the water thrown from the

impeller and directs it in a single direction.

• Backing Plate:

Behind the volute case is the backing plate. The backing plate seals the back of the volute

case area.

• Stufﬁng Box:

Attached to, and sometimes part of, the backing plate is the stufﬁng box. Stufﬁng Box -

That portion of the pump that houses the packing or mechanical seal. Usually referred

to as the dry portion of the pump. The stufﬁng box is located in back of the impeller and

around the shaft.

• Shaft:

The impeller is attached to a shaft. The shaft is often made of steel or stainless steel to

support the impeller. The sizes of the shafts must be measured accurately. An undersized

shaft may increase pump vibration, reduce bearing life, cause shaft breakage, and shorten

7.3 Positive Displacement Pump

201

the overall pump life. On the other hand, an oversized shaft can unnecessarily increase the

pump costs.

• Shaft Sleeve:

Usually, a portion of the shaft located below the seals is covered with a shaft sleeve. The

shaft sleeve is made of a metal, generally bronze or stainless steel. It is designed to oper-

ate with the ability to slide or thread on the shaft. The shaft sleeve is applied to properly

position the impeller on the shaft as well as to protect the shaft.

Figure 7.12: Shaft sleeve threaded to shaft

• Seals:

–

The place where the shaft passes through the casing is the stufﬁng box must be sealed

to prevent the pressurized water from the "wet" end of the pump to escape the rotat-

ing shaft in the stufﬁng box.

–

Typically either a mechanical seal or a packing seal (traditional method) are used for

stopping this leakage.

– Packing/Mechanical Seals:

Packing and mechanical seals serve the same purpose: they control leakage through

the stufﬁng box.

Packing: A packing is composed of some type of ﬁber, like cotton, and some

type of lubricant, like graphite or Teﬂon. Packing seals are rings of braided,

ﬁbrous material. are housed in a are “stuffed” into a pump stufﬁng box (or seal

chamber), located around the outside diameter of the pump shaft, to reduce the

amount of pumped medium that is forced out of the pump along the drive shaft.

Mechanical seal: A mechanical seal is composed of two ﬁnely machined sur-

faces, one hard and one soft, that prevent water from passing. When installing

packing, joints should be staggered.

Stufﬁng Box

Braided Packing

Mechanical Seal

202

• Packing Gland:

Chapter 7. Pumping Systems

In order to control leakage with packing, pressure must be placed on the packing. This

pressure is applied by the packing gland, two pieces of metal at the back of the stufﬁng

box. There should be a slow drip from the stufﬁng box to show lubrication between the

shaft and the packing.

• Lantern Ring:

It is often desirable to lubricate and cool the packing with external water or oil. When

water is used, it is called seal water or ﬂush water. The seal water is distributed into the

stufﬁng box through the lantern ring, which is commonly a brass ring with holes that allow

the water to easily pass.

•

Gland: The gland is located around the shaft of the pump and bolts to the face of the stuff-

ing box directly on the pump casing. The gland nut allows the packing material to be

compressed to form a watertight seal and prevent leakage of the pumped water.

Both, packing seals and mechanical seals, rely on seal water for effective operation. Seal

water serves three main purposes: to cool the seal and the shaft, to lubricate the seal and to

ﬂush away impurities in the system.

7.4 Pump Calculations

•

Pump is a machine used for moving water (and other ﬂuids) through a piping system and

raise the pressure of the water.

•

Pumping is accomplished by transforming the input energy - typically from an electric

motor or from other sources such as high-pressure air.

• The pump calculations in this section are for electrically driven rotodynamic pumps.

• To move water, a pump will need to overcome resistance due its density, gravitational force

and friction.

• This resistance is dependent on:

–

Height the water needs to be raised. This height of the ﬂuid in a container is referred

to as head.

– Quantity of water involved

7.4.1 Glossary of Pump Calculations Terms

Force: In the English system force and weight are often used in the same way. The weight of

the cubic foot of water is 62.4 pounds. The force exerted on the bottom of the one foot cube is

62.4 pounds. If we have two cubes stacked on top of one another, the force on the bottom will be

124.8 pounds.

Pressure: Pressure is a force per unit of area, pounds per square inch or pounds per square foot

are common expressions of pressure. The pressure on the bottom of our cube is 62.4 pounds

per square foot. It is normal to express pressure in pounds per square inch (psi). This can be

accomplished by determining the weight of one square inch of our cube one foot high. Since the

7.4 Pump Calculations

203

cube is 12 inches on each side, the number of square inches on the bottom surface of the cube is

12×12 = 144in². Now by dividing the weight by the number of square inches we can determine

the weight on each square inch.

Head: Pressure is directly related to the height of a column of ﬂuid. This height is called head or

feet of head. Pressure and feet of head head are directly related - for every one foot of head there

is a pressure of 0.433 psi.

0.433 psi

ft (water column)

1 ft (water column)

2.31 psi

Thus,

or conversely

Note: This pressure/head will include the height the water pumped and also the head asso-

ciated with friction losses - energy loss because of the water moving through the pipe and

ﬁttings.

Force

Pressure =

Area

12"

Pressure exerted by

a 1ft column of water

62.4 lb

12in x 12in

= 0.43 psi

12"

As 1ft³of water weighs 62.4 lbs

12"

The pressure at the bottom of a container is affected only by the height of water in the container

and not by the shape or the volume of the container. In the drawing below there are four contain-

ers all of different shapes and sizes. The pressure at the bottom of each is the same.

The pressure exerted at the bottom of a tank is relative only to the head on the tank and not the

volume of water in the tank. For example, below are two tanks each containing 5000 gallons.

The pressure at the bottom of each is 22 psi. If half of the water were drained from the tanks the

pressure at the bottom of the elevated tank would be 17.3 psi while the pressure at the bottom of

the standpipe would be 11 psi.

204

Chapter 7. Pumping Systems

Velocity: Velocity is the speed that the water is moving along a pipe or through a basin. Velocity

is usually expressed in feet per second, ft/sec.

Flow: Flow is commonly expressed in gallons per minute (gpm) and/or cubic feet per second

(cfs). There is a relationship between gallons per minute and cubic feet per second. One cubic

foot per second is equal to 448.8 gallons per minute.

1cfs = 448.8gpm

Flow Equation; The basic equation for determining ﬂow is as follows:

Q = V ×A

Where:

Q = cfs ft³/sec

ꢀ

ꢁ

V = ft/sec

A = ft²

Static Pressure: Static implies a non-moving condition. The pressure measured when there

is no water moving in a line or the pump is not running is called static ³²pressure. This is the

pressure represented by the gauges on the tanks in the discussion above.

Dynamic Pressure/Velocity Head: When water is allowed to run through a pipe and the pres-

sure (called pressure head) measured at various points along the way we ﬁnd that the pressure

decreases the further we are from the sources. The amount of energy required to bring a ﬂuid

from standstill to its velocity. For a given quantity of ﬂow, the velocity head will vary indirectly

with the pipe diameter.

Headloss: The reason for this reduction in pressure is a phenomenon called headloss. Headloss

is the loss of energy (pressure) due to friction. The energy is lost as heat.

If the headloss in a certain pipe is 25 feet, it means the amount of energy required to overcome

the friction in the pipe is equivalent to the amount of energy that would be required to lift this

amount of water straight in the air 25 feet.

In a pipe, the factors that contribute to headloss include the following:

7.4 Pump Calculations

205

• Roughness of pipe - If the roughness of a pipe were doubled the headloss would double.

• Length of pipe - If the length of the pipe were doubled the headloss would double.

• Diameter of pipe - If the diameter of a pipe were doubled the headloss would be cut in half

•

Velocity of water - If the velocity of the water in a pipe were doubled the headloss would

be increased by about four times. It should be apparent that velocity, more than any other

single factor, affects headloss. To double the velocity we would have to double the ﬂow in

the line.

•

Pumping System Components and Fittings - Each type of ﬁtting has a speciﬁc headloss

depending upon the velocity of water through the ﬁtting. For instance the headloss though

a check valve is two and one quarter times greater than through a ninety degree elbow and

ten times greater than the headloss through an open gate valve.

Static Head: Static head is the distance between the suction and discharge water levels when

the pump is shut off.

Suction Lift:

•

A pump is said to be in a suction lift condition any time the eye (center) of the impeller is

above the water being pumped. Suction lift is the distance between the suction water level

and the center of the pump impeller.

A suction lift simply means the maximum level of the liquid to be pumped is physically

below the centerline of the pump impeller. Most centrifugal pumps can operate with a

suction lift if they are primed ﬁrst.

•

Primed means the suction line, pump casing and impeller are full of liquid and all of the

air or non-condensable gases are removed.

A centrifugal pump cannot “suck” or ‘lift” the liquid into itself. Atmospheric pressure is

the force pushing the liquid into the pump for open systems. From this information we

can conclude; the maximum suction lift - theoretical lift at sea level with a perfect pump,

a perfect liquid and a frictionless leak free system can approach 34 feet (Atmospheric

pressure at sea level is 14.7 psia X 2.31 = 34).

•

Because a perfect vacuum is never achieved and because some lift is lost to friction in

the suction line, the maximum actual suction lift for a positive-displacement pump is

approximately 22 ft.

•

The maximum actual suction lift for a centrifugal pump is approximately 15 ft when pump-

ing water from an open air tank.

Positive-displacement pumps can operate with lower suction pressures or high suction lifts

because they can create stronger vacuums.

Suction lift will be greater if the pressure in a closed tank is greater than atmospheric

pressure.

Total Dynamic Head (TDH): The total energy needed to move water from the center line of a

pump (eye of the ﬁrst impeller of a lineshaft turbine) to some given elevation or to develop some

given pressure. This includes the static head, velocity head and the headloss due to friction.

Horsepower: Horsepower is a measurement of the amount of energy required to do work. Mo-

206

Chapter 7. Pumping Systems

tors are rated in horsepower. The horsepower of an electric motor is called brake horsepower.

The horsepower requirements of a pump are dependent on the ﬂow and the total dynamic head.

33,000 foot pounds per minute of work is 1 horsepower. The horsepower output of an electric

motor is directly reﬂected to the amperage that the motor draws. Any increase in horsepower

requirements will give a corresponding increase in amperage.

Suction Head: Suction head is the distance between the suction water level and the center

of the pump impeller when the pump is in a suction head condition. A pump is said to be in a

suction head condition any time the eye (center) of the impeller is below the water level being

pumped.

Velocity Head: Velocity head is the amount of energy required by the pump and motor to over-

come inertia and bring the water up to speed. Velocity head is often shown mathematically as

V²/2 g. ( g is the acceleration due to gravity −32.2ft/sec²).

Cavitation: Cavitation in pumps is the rapid creation and subsequent collapse of air bubbles

occuring as a result of the inlet pressure falling below the design inlet pressure or when the

pump is operating at a ﬂow rate higher than the design ﬂow rate. This collapse of the air bubbles

typically manifests as a pinging or crackling noise. Cavitation is undesirable because it can

damage the impeller, cause noise and vibration, and decrease pump efﬁciency.

7.4 Pump Calculations

207

Figure 7.13: Pumping heads illustration

Chapter 7 Assessment

1. Name the type of valve that is sometimes found on the suction side of a centrifugal pump

and is located where the water enters the casing.

a. Check valve

b. Gate valve

c. Altitude valve

d. Pressure relief valve

e. Foot valve

2. After a pump is shut off but continues to run backwards indicates:

a. The bearings are failing

b. The packing needs tightening

c. The main lock nut needs to be tightened

d. The check valve is leaking

e. A valve on the discharge side of the pump is shut

3. Wear rings are installed in a pump to:

a. hold the shaft in position

b. keep the impeller in place

c. keep wear concentrated on economically replaceable part

d. wear out the sleeve

4. Pump motors draw more power starting than during normal operating conditions because:

a. check valves have to be pushed open

b. energy is required to get the water moving

210

Chapter 7. Pumping Systems

c. the motor and pump have to start turning

d. all of the above

5. Head is measured in

a. absolute pressure.

b. gauge pressure.

c. feet.

d. foot-pounds.

6. To ease installation of impeller wear rings, they can be

a. lubricated with a light oil.

b. greased with lithium.

c. heated.

d. cooled.

7. Packing is designed to

a. add lubricant to the shaft.

b. expand and deteriorate with normal use.

c. protect the shaft.

d. wear and deteriorate with normal use.

8. Bearings on a line shaft turbine can be lubricated with

a. oil or water.

b. grease or oil.

c. lithium or grease.

d. graphite or grease.

9. Packing replacement is usually performed when

a. water leakage sprays out of the pump housing.

b. no further tightening can be done on the packing gland.

c. the packing gland bolts are exposed by more than 2^1/2inches above the nut.

d. the packing has completely disintegrated.

10. Which is at the top of a stufﬁng box?

a. Packing gland

b. Lantern ring

c. Mechanical seal

d. Seal cage

11. Which assembly holds the lantern ring and packing?

a. Shaft assembly

b. Casing ring assembly

c. Packing gland casing

d. Stufﬁng box

12. Which of the following prevents the impeller of a pump from turning on the shaft?

a. Lock nut on threaded shaft

b. Key

7.4 Pump Calculations

211

c. Steel pin

d. Caliper pin

13. Which device serves the same function as the packing?

a. Inline suction gland

b. Packing gland

c. Mechanical seal

d. Lantern seal

14. Vertical turbine pumps that are used in wells may be oil-lubricated or water-lubricated.

Operators should use extreme care not to start any water-lubricated pump before making

sure that the:

a. Valve on discharge side is open.

b. Bearings are dry.

c. Valve on suction side is closed.

d. Bearings are wet.

15. The head against which a pump must operate:

a. Is the sum of the static head and the head due to friction loss.

b. Must always be above the shut-off head.

c. Is the static head.

d. Is the friction head.

16. What term describes the condition that exists when the source of the water supply is below

the centerline of the pump?

a. Pressure head

b. Velocity head

c. Suction lift

d. Total discharge head

17. What is the most common use today for a positive-displacement pump?

a. Raw water intake pump

b. System booster pump

c. Chemical feed pump

d. Filter feed pump

18. A pumping condition where the eye of the impeller is above the water is called?

a. Dry Well

b. Suction Head

c. Wet Well

d. Suction Lift

19. The force used in an End-suction pump is called

a. Pressure

b. Centrifugal

c. Velocity

d. Kinetic

212

20. __ is the loss of energy as a result of friction.

Chapter 7. Pumping Systems

a. Velocity loss

b. Headloss

c. Elevation Loss

d. Pump Loss

21. As the water travels around the volute towards the discharge line the total energy shifts

from

a. High Velocity Head to low PSI b. Low Velocity Head to high PSI c. Low Velocity Head

to low PSI d. High Velocity Head to high PSI

22. The part that in an End Suction pump that is used to collect the liquid discharged from the

impeller is called?

a. Shaft

b. Packing

c. Suction Head

d. Volute

23. Head is the energy that a body has by virtue of its position or state.

a. Velocity

b. Potential

c. Kinetic

d. Pressure

24. An impeller that has no shrouds and used to pump ﬂuid with large objects is called?

a. Semi-open

b. Open

c. Closed

d. Very-closed

25. A pump station design where the eye of the impeller is submerged in water is called?

a. Dry Well

b. Suction Head

c. Wet Well

d. Suction Lift

Chapter 8

VIII

Water Distribution . . . . . . . . . . . . . . . . . . . 209

Introduction

8.1

8.2

8.3

8.4

8.5

8.6

8.7

Pipelines

Storage Systems

V a lves used in Water Distribution

Fire Hydrants

Water Meters

Distribution System Operation and Maintenance

Elements

8. Water Distribution

Expected Range of Knowledge for Water Distribution

Water Distribution System Operator License Exams

Knowledge of basic operation

Knowledge of start-up procedures

Ability to ﬂush a service line

Ability to recognize a cross-connection

Ability to recognize a potential backﬂow hazard

Ability to tap a water main

Knowledge of "back-pressure" and "back-siphonage" conditions

Knowledge of "grid," "tree„" "arterial," and "dead end" water systems

Knowledge of available backﬂow prevention methods

Knowledge of conditions that cause backﬂow

Knowledge of equipment used for ﬂushing

Knowledge of pressure/elevation relationships

Knowledge of proper ﬂushing velocities

Knowledge of service connection materials and ﬁttings

Knowledge of the impacts of ﬂushing on a distribution system

Ability to connect water pipe

Ability to operate a dewatering pump

Ability to set up a temporary service line

Knowledge of bedding techniques

Knowledge of compaction tools and methods

Knowledge of excavating techniques

Knowledge of notiﬁcation requirements

Knowledge of proper backﬁll techniques

Knowledge of proper ﬂushing procedures

216

Expected Range of Knowledge for Water Distribution

Chapter 8. Water Distribution

Water Distribution System Operator License Exams (Continued)

Ability to ﬂush using a hydrant

Knowledge of hydrant types

Knowledge of hydrant valve operation/testing

Knowledge of mechanical parts of hydrants

Knowledge of pressure requirements

Knowledge of proper hydrant installation

Knowledge of thrust blocks

Knowledge of maintenance recordkeeping

Knowledge of predictive, preventative, and corrective maintenance

Ability to differentiate pipe tap size

Ability to recognize abnormal operating conditions

Ability to recognize faulty or damaged pipe

Knowledge of compatible materials

Knowledge of material compatibility

Knowledge of pipe connectors and applications

Knowledge of pipe ﬁtting and joining methods

Knowledge of pipe locating methods

Knowledge of pipe material and applications

Knowledge of pipe material compatibility

Knowledge of proper backﬁll procedures and compaction

Knowledge of proper bedding techniques

Knowledge of proper joints and ﬁtting applications

Knowledge of system pressure zones

Knowledge of AC pipe handling procedures

Ability to recognize a malfunctioning valve

Knowledge of pressure regulating valve maintenance

Knowledge of proper valve installation

Knowledge of the principles of operation of valves

Knowledge of valve types and applications

Ability to choose the correct meter size

Ability to differentiate meter size

Knowledge of water meter types and purposes

Knowledge of AWWA disinfection standards for storage facilities

Knowledge of AWWA disinfection standards for water mains

Knowledge of AWWA disinfection standards for wells

Knowledge of storage reservoir disinfection techniques

Ability to recognize corrosive conditions in distribution systems

Knowledge of the causes of corrosion in a distribution system

Knowledge of the effect of corrosion in a distribution system

Knowledge of type and applications of cathodic protection devices

Ability to differentiate between a "trunk" line and a "transmission" line

Ability to drain, clean, and disinfect a storage facility

Ability to interpret map symbols

Ability to recognize when ﬂushing is required

217

Expected Range of Knowledge for Water Properties and Sources

Water Distribution System Operator License Exams (Continued)

Knowledge of ﬂushing techniques

Knowledge of map types

Knowledge of storage facility components

Knowledge of storage facility corrosion control methods

Knowledge of the terms, "peak demand," "peak hour demand," "maximum daily demand," and

"per-capita demand"

Knowledge of the types of storage facilities and their applications

Ability to identify different soil types

Knowledge of dewatering techniques

Knowledge of pipe cleaning procedures

Knowledge of the causes and effects of tuberculation

Knowledge of the ﬁre hydrant testing program

Ability to choose the correct type of joint

Knowledge of advantages/disadvantages of pipe materials

Knowledge of allowable leak loss

Knowledge of C-Factor

Knowledge of factors affecting leak detection

Knowledge of leak detection methods

Knowledge of proper disinfection techniques

Knowledge of proper thrust block uses

Knowledge of proper thrust restraint

Knowledge of tapping methods

Knowledge of tapping tools/equipment

Knowledge of thrust restraint requirements

Ability to interpret SCADA information

Knowledge of communication techniques

Knowledge of the components of a SCADA system

Knowledge of pressure ratings

Knowledge of valve exercise program

Knowledge of mechanical parts of water meters

Ability to calculate a water velocity

Knowledge of ﬂow demand requirements

Knowledge of permit requirements for ﬂushing

Ability to choose the proper cleaning technique

Ability to recognize tuberculation

Knowledge of storage tank corrosion control measures

Ability to calculate a hydraulic gradient

Knowledge of power requirements (e.g. efﬁciency)

Ability to calculate annual expenditures

Knowledge of local water usage patterns

Knowledge of water rate structures, water rate setting methods

218

Chapter 8. Water Distribution

Expected Range of Knowledge for Water Properties and Sources

Water Treatment Operator License Exams

Knowledge of storage tank disinfection procedures

Ability to read and interpret water meter readings

Knowledge of the components of water meters

Knowledge of the operation of water meters

Knowledge of water meter types and uses

Knowledge of head pressure

Knowledge of the operation of pressure gauges

Knowledge of basic SCADA system components

Ability to calibrate a water meter

Ability to replace pressure gauges

Ability to calibrate a pH meter

Ability to determine normal operation of a SCADA system

Ability to administer a maintenance program

Knowledge of C-factor

Knowledge of the cathodic protection process

Knowledge of corrosion control inhibitors

Ability to develop an operational site sampling plan

Ability to develop an operations plan

Ability to evaluate treatment facility performance

Knowledge of facility operation and maintenance

Knowledge of management principles

Knowledge of principles of supervision

Knowledge of public relations principles

8.1 Introduction

219

8.1 Introduction

•

The basic function of a water distribution system is to transport the water from the treat-

ment facility to the customer.

• In addition, distribution systems may also provide:

1. Storage

2. Provide ﬂow and pressure adequate for ﬁre protection

3. Provide a point to sample water to ensure the end user is being provided with water

that is safe and meets the regulatory requirements.

•

As the volume of water necessary to ﬁght ﬁres is much greater than domestic and commer-

cial water demand in most communities, the size of water mains, pump station capacity,

and storage reservoir volume is determined by ﬁre suppression needs.

• Distribution systems should provide adequate and reliable water to the customer.

• Adequate means:

– Providing all the water the customer needs at a pressure not less than 20 psi.

– Water provided meets the customer’s needs for quality.

• Reliable means:

–

Reliable means that customers can expect to obtain all the water they need, anytime

they need it. In other words, they can expect that there will be water at the tap.

•

As part of being adequate and reliable, the system must be operated in a way so that the

quality of the water does not deteriorate between the treatment facility and the customer.

In most communities it is expected that adequate ﬂow, pressure, and storage volume is

available for ﬁre prevention

• The scope of this text is to describe the details of the piped distribution system.

•

Basic components of the piped distribution system includes: pipes, valves, ﬁre hydrants,

service connections, and reservoirs. Piped systems may also have pumping stations which

are discussed in another Module.

•

Per Title 22 Regulations, the minimum operating pressure in the water main at the user

service line conectionshould be 20 psi at all times.

• Characteristics of and ideal distribution system:

– Sized appropriately to accommodate system ﬂows including ﬁre ﬂows.

– Minimally impact water quality

– Provide water at appropriate line pressures.

– Built with components that are durable and corrosion resistant.

• Primary components of the distribution system include:

1. Pipelines. which include:

– Transmission Mains

– Distribution Mains

– Service Laterals

2. Facilities

220

Chapter 8. Water Distribution

– Storage Structures

– Pump Stations

– Pressure Reducing Stations

3. Appurtenances

– Valves

– Angle Joints

– Fire Hydrants

– Meters

•

The friction between the inside surface of the pipe and the water ﬂowing through it, pro-

vides a resistance to the ﬂow. This resistance depletes the energy of the ﬂowing water, and

is therefore important to ensure the pipe inside surface is smooth.

Besides the pipe, other components of the water distribution system including ﬁttings,

bends, valves, expansion joints and any change in direction can also create friction that

causes energy/pressure loss.

"C" factor is a measured value which quantiﬁes the smoothness of the interior of a pipe.

For most pipe materials C ranges from 60 - 150. A high C value implies less friction or

a smoother pipe, greater water carrying capacity, and the smaller the friction or energy

losses from water ﬂowing in the pipe. A CPVC pipe has a C factor value of 150 whereas

the C factor of a worn/pitted cast iron pipe would be about 60-80.

8.2 Pipelines

Pipelines are arteries and veins of a water distribution system. They are in a variety of lengths

and sizes and deliver water throughout a wide range of areas. They are typically categorized as:

transmission mains, distribution mains, and service laterals.

8.2.1 Transmission Mains

Transmission mains are large diameter pipes, carrying large volumes of water to the distri-

•

bution system.

•

Not all water suppliers have transmission mains of this size and some may not travel long

distances.

Typically there are no service connections to customers off transmission mains unless they

are smaller in size and are located within a distribution system.

• Transmission mains are commonly welded steel and ductile iron pipe.

•

All newly installed water mains shall comply with the materials and installation standards

of the American Water Works Association (AWWA).

8.2.2 Distribution Mains

California Code of Regulations require water mains to have a nominal diameter of at least

four-inches. Typical Distribution mains range in size from 6 inches up to 24 inches in

•

8.2 Pipelines

221

diameter.

• Unlike transmission mains, distribution mains have customer services connected to them.

Distribution mains are most commonly ductile iron pipe. However, polyvinyl chloride is

also extensively used. Asbestos cement pipe is found only in older water systems.

• Table 8.1 summarizes the advantages and disadvantages of the distribution mains:

•

SYSTEM

ADVANTAGES

DISADVANTAGES

•

Does not maintain

satisfactory pressure in

high-rise buildings.

As one pipe provides

the water to the entire

building - quite risky.

High head loss, req.

larger dia. piping

•

Dead-end or Tree Distribution Sys-

tem

•

Pipe laying is simple

and easy.

Fewer cut-off valves are

required - lower O&M

costs.

Maintenance done

without disrupting ﬂow

In this type of water distribution

system, one main pipeline runs

through the center of the building,

and the sub-mains branch lines

off from both sides. The sub-main

lines are divided into several

branch lines for service connection

to a particular house.

•

System discharge

•

capacity is limited.

Dead-ends can cuase

water quality problems

and require frequent

ﬂushing.

•

The length of pipe

laying is more which

ultimately leads to

higher cost.

Several valves are

required to control the

ﬂow and discharge of

water.

Ring Distribution System

•

Discharge rate is high,

low head losses

Maintenance can be

done without disrupting

ﬂow

No endpoints, minimal

stagnation

Here, the main pipeline encloses

the system. The branch pipes are

connected cross-wise to the mains

and also to each other.

•

Typically used in high-

rise buildings.

Discharge rate is high,

low head losses.

Maintenance can be

done with minimal ﬂow

disruption.

No endpoints, minimal

stagnation

In this types of water distribution

system, the whole buildings are

divided into several distribution

areas. Each building has a centrally

located elevated reservoir from

where distribution pipes run radi-

ally towards the periphery of the

distribution areas.

•

The design of the pipe

laying system is compli-

cated.

More length of pipe is

required.

Radial Distribution System

•

In this system, more cut-

off valves are required.

This system requires

longer pipe lengths with

larger diameters.

The analysis of dis-

charge, pressure, and

velocity in the pipes is

difﬁcult and cumber-

some.

Grid Iron Distribution System

•

Minimal stagnation or

sediment deposit.

Main supply lines run through

the center, and sub mains branch

off in perpendicular directions.

The branch interconnects the

sub-mains. All types of pipes are

interconnected - no dead ends.

Water can reach any given point

from many directions, which

allows more ﬂexible operation,

particularly for repairs.

Water is available

at every point with

minimum loss of head.

Water is delivered with

adequate pressure for

ﬁreﬁghting.

•

During repair, few

houses are affected.

Table 8.1: Types of Distribution Systems

8.2.3 Service Laterals

•

A service lateral is the pipe that provides water from the water main in the street to a home

or business.

For residences this pipe is usually 1 inch in size and runs from the water main into the

home where the water meter is installed.

Service lateral is typically connected to the main line through a brass plug valve called a

corporation stop.

A curb stop is a brass plug valve installed at the water meter inside the valve box. The curb

stop is used to shut off the water ﬂow to the user.

Figure 8.1: Typical Service Lateral Installation

8.2.4 Piping Material

The attributes for good pipe materials include:

• It should have adequate structural strength.

• Impervious, corrosion-resistant, durable and long, lasting.

• Cost-effective.

• Resistance to abrasion.

• Light weight so that easy to transport and handle.

• Easy to join, ﬂexible in design, easy to repair and maintain.

• Environmentally friendly.

•

Ease of locating piping without excavation - pipes with electrical conductive material

may be detected using electromagnetic metal detectors whereas pipes made from non-

conductive material maybe detected by inducing a signal into the pipe from a valve or

hydrant that may be picked up by an above-ground sensor.

Tables 8.2 and 8.3 summarize the properties, advantages, disadvantages and joints related to the

common distribution system pipeline materials.

Pipe Material

Advantages

Disadvantages

Joints

•

Numbers of joints are less because these

are available in long lengths.

• Maintenance cost is high.

Steel: These are fabricated by rolling the

mild steel plates to proper diameter and can

be joined by riveting or welding. Steel pipe

is coupled by a variety of methods; threaded

couplings, welded couplings, Dresser™type

couplings, Victaulic™couplings, ﬂanges

and rubber ring push-on joints.

• The pipes are cheap at the ﬁrst cost.

•

The pipes are likely to be rusted by acidic

or alkaline water.

Steel pipe is coupled by a variety of

methods; threaded couplings, welded

couplings, Dresser™type couplings, Vic-

taulic™couplings, ﬂanges and rubber ring

push-on joints.

•

The pipes are durable and strong enough

to resist high.

•

The pipes require more time for repairs

during breakdown and hence are not

suitable for distribution pipes.

•

The pipes are ﬂexible to some extent

laid on curves. and they can therefore

5. Transportation is easy because of

lightweight.

•

The co-efﬁcient of expansion for plastic

is high.

It is difﬁcult to obtain plastic pipes of

uniform composition.

• Cost of these pipes is moderate.

• Pipes are cheap and durable.

PVC Class and Pressure pipe can be con-

nected using either an integral bell and

spigot process or a double ended bell. In

either case the gasket is a rubber material

and the joints are made by lubricating the

pipe and pushing it into the coupling or bell.

•

The pipes are ﬂexible, light in weight and

they can easy to mold any shape.

• Polyvinyl chloride (PVC)

• Cross linked PVC (CPVC)

• The pipes are less resistant to heat.

•

Does not corrode, tuberculate or support

bacteria growth like metal pipe.

Some pipes of plastic impart taste to the

water.

•

Comparatively DI pipes possess greater

ductility and impact resistance than CI

pipes.

Ductile cast iron pipe is commonly con-

nected using mechanical joints (M.J.),

ﬂanges or the various common rubber ring

push-on joints. Fittings used are commonly

made of gray or ductile cast iron and use

M.J. or hub joints. Service taps are made

by directly tapping the line or using service

saddles.

•

The pipes require internal and external

lining or protection.

Corrosion may take place as equal in CI

pipes.

The polyethylene wrappings may cause

damage.

Ductile iron (DI): Typically, the pipe is

manufactured using centrifugal casting

in metal or resin-lined molds. Protective

internal linings and external coatings are

done to ductile iron pipes to overcome

corrosion problems.

•

Lighter than CI pipes so that easy to

handle and transport.

The pipes are easy to join and simple

also can accommodate some angular

deﬂection.

These pipes are of more strength than CI

pipes.

•

There are pipes that are most durable

with usual life of about 75 years.

The pipes can be cast at site work and

thus there is the reduction in transport

charges.

• Transportation is difﬁcult.

• Repair work is difﬁcult.

• Initial cost is high.

Concrete Pipe: Cement concrete pipe pipes

may be either plain cement or reinforced

cement concrete. PCC pipes can be used

up to 15 m head whereas RCC pipes can be

used up to the head of 60 in and for higher

head pre-stressed concrete can be used.

This pipe is connected by bell and spigot

rubber ring pushon joints. Once the joint

has been connected the exposed steel must

be coated with concrete to protect the steel

cylinder from corrosion.

• Maintenance cost is less.

•

These pipes are affected by acids, alka-

lies, and salty waters.

Inside surface of the pipe can be made

smooth.

• No danger of rusting.

Table 8.2: Pipe Material of Construction - 1 of 2

Pipe Material

Advantages

Disadvantages

Joints

•

PEX has a perfect blend of rigidity and

ﬂexibility.

These pipes are able to withstand high

water pressure.

Their structural integrity is not compro-

mised if they are bent and woven through

walls, ceilings, and basements.

These pipes are easy to cut and mold and

do not require any complex tools to do

so.

The most common connection for HDPE

pipe is a heat fused weld. The pipe is com-

monly connected using a butt welding

process. There are special stainless steel

adapters that allow the pipe to be con-

nected using the Victaulic type of coupling.

Flanged connections can be made by weld-

ing a butt or socket weld ﬂange to the pipe.

Repairs can be made to the pipe using typi-

cal cast iron couplings, providing a special

stainless steel insert is placed in the pipe to

prevent collapsing of the pipe.

•

Due to their relatively young age, long

term capabilities still remain untested and

they are yet to be approved for building

codes in several jurisdictions.

They also are not compatible with all,

or even most, ﬁttings and leaks are a

common occurrence.

Polyethylene:

•

• Crosslinked polyethylene (PEX)

• High density polyethylene (HDPE)

•

It is environmentally unfriendly as it is

non-recyclable.

• They are relatively inexpensive.

AC pipe undergoes gradual degradation in

the form of corrosion (i.e., internal calcium

leaching due to conveyed water and/or ex-

ternal leaching due to groundwater). Such

leaching leads to reduction in effective

cross-section, which results in pipe soften-

ing and loss of mechanical strength. These

pipes can contain up to 20 per cent asbestos

which poses health risks.

The material is connected together using

a double bell coupling with a rubber ring

in each end. Fittings and valves used on

AC pipe are commonly made of cast iron

using a rubber push-on ring for connection.

Service line connections may be made

by direct tapping of the line or by using a

service saddle.

Asbestos Cement (Transite or AC)): Was

used extensively in the mid-1900s in

potable water distribution systems, par-

ticularly in the western United States. The

AC lifespan estimates were at 70 years, but

actual service life depends largely on pipe

condition and working environment.

The pipes were cheap to produce, and at the

time, thought to be resistant to internal and

external corrosion.

Table 8.3: Pipe Material of Construction - 2 of 2

8.2 Pipelines

225

8.2.5 Basic Water Main Installation

•

California Code of Regulations, Title 22, Division 4, Chapter 16, Section 64572 estab-

lishes criteria for the separation of new water mains from non-potable pipelines. These

standards include:

–

New water mains and new supply lines shall not be installed in the same trench as

and shall be at least 10 feet horizontally from and one foot vertically above, any

parallel pipeline conveying untreated/treated sewage, disinfected secondary recycled

water or hazardous ﬂuids such as fuels, industrial wastes, and wastewater sludge.

New water mains and new supply lines shall be installed at least 4 feet horizontally

from, and one foot vertically above, any parallel pipeline conveying tertiary

recycled water, and storm drainage.

New water mains shall not be installed within 100 horizontal feet of the nearest

edge of any sanitary landﬁll, wastewater disposal pond, or hazardous waste

disposal site, or within 25 horizontal feet of the nearest edge of any cesspool,

septic tank, sewage leach ﬁeld, seepage pit, underground hazardous material

storage tank, or groundwater recharge project site.

–

•

Water main installation begins with excavation which is expensive and dangerous. Before

excavation can begin, the project must be well planned and all safety elements must be

considered.

•

To protect the trench and workers from trafﬁc, the excavated material should be piled on

the pavement side of the trench.

Place all excavated or ﬁll materials a minimum of two feet away from the top edge of the

trench. If materials need to be closer than two feet from the edge of the trench, install an

effective barrier to prevent them from falling into the excavation.

4. Before entering the trench, determine if shoring is necessary.

• OSHA requires a protective system for trenches 5 feet or greater.

5. Determine if a hazardous atmosphere exist in the trench.

•

Normal oxygen levels range from 19.5 to 21.5%.

6. Determine if access to and exit from the trench is required.

• Trenches 4 feet or more in depth must have a safe means of egress.

•

Spacing between ladders or other means of egress must be such that a worker will not have

to travel more than 25 feet laterally to the nearest means of egress.

• Ladders must be secured and extend a minimum of 36 inches above the landing.

After the trench is prepared, inspect the pipe.

• Inspect the pipe for defects, damage, oil, dirt, grease, and/or foreign matter.

•

Any unsound material should be replaced and all foreign matter or dirt should be removed

from the interior of the pipe before lowering into the trench.

Before lowering the pipe into the trench the trench bottom should be smooth and free of material

like large stones or large dirt clods.

226

Chapter 8. Water Distribution

Lower the pipes, and other necessary equipment carefully into the trench.

Before connecting the pipe:

• Inspect the bell to be sure that no dirt or foreign material is on the ring.

•

Clean the pipe end around the entire circumference from the end spigot to 1 inch above the

reference line (note: this line is used for proper insertion depth of bell and spigot).

Once the pipe is cleaned, be careful during installation to ensure gravel does not enter into

the line.

•

Be sure to use blocks or restraints to avoid leaks and pipe movement from the thrust against tees,

valves, bends, reducers and ﬁre hydrants.

•

Size and type of the thrust block depends on maximum pressure, pipe size, kinds of soil

and types of ﬁttings. After the water main pipe and ﬁttings have been installed in the

trench, the excavation must be backﬁlled with suitable material.

Only clean sand or selected soil should be used for the ﬁrst layer. The bedding around the

pipe should be of uniform size and material. Allowing materials of various sizes such as

large rocks could cause the pipe to fracture during settlement.

The ﬁrst layer of backﬁll should be placed equally on both sides of the pipe, up to about

the center of the pipe. This material should then be compacted, a process often called

haunching.

•

Depending on the area and conditions, generally another layer of backﬁll is placed over the

pipe and again compacted to protect and secure the pipe.

The trench needs reﬁlled appropriately. The backﬁll material should be compacted at 12

inch intervals to minimize settlement.

Backﬁll practices vary depending on type of pipe, local soil conditions and regulatory

requirements. Proper backﬁlling is very important:

• Improper compaction = broken lines

• Large backﬁll = increase probability of main break

All new sections of water mains must be thoroughly disinfected.

•

To properly disinfect water mains, different methods can be applied. Due to the dangers

of chlorine it is advised that the operator choose the best method that suits the facility’s

needs.

•

Calcium hypochlorite tables can be placed in each section of pipe and ﬁre hydrant as work

progresses.

• A concentrated chlorine solution can be injected through a corporation stop.

•

The chlorination rate should be such that it will produce a concentration of about 50mg/L

when mixed with incoming water.

• Mathematical calculations are necessary to determine how much chlorine will be needed.

• This will be addressed in the chlorination section.

• The chlorine solution should remain in the pipe for at least 24 hours.

After the trench has been backﬁlled, the new main must be pressure tested to determine whether

there are any leaks.

8.3 Storage Systems

227

•

The test may be performed one section at a time between valves or the installer may wait

and test the entire job at one time.

At the end of the contact period, the chlorinated water should be ﬂushed from the pipeline.

•

One or more ﬁre hydrants should be used for ﬂushing so that a velocity of around 5ft/s is

obtained in the pipe.

•

This velocity should be maintained long enough to allow two or three complete changes

of water and for the water to run visibly clean. - Gravel in the line is an indication of im-

proper installation.

•

The highly chlorinated water will probably kill grass, so the ﬂow should be carried to a

disposal site through hoses.

• In some cases, the water may need dechlorinated before it is released to a waterway.

After a new pipeline has been disinfected and ﬂushed, it should be reﬁlled with water from the

distribution system and tested for bacteriological quality.

• This test takes at least 24 hours to complete from the time of sampling.

• The test must meet requirements of the Department of Environmental Protection.

8.3 Storage Systems

• Water storage reservoir in a water distribution system allows for:

1. Maintaining water supply pressure - typically maintained by the water level in the

storage reservoir.

2. As water demand changes during the day, the water reservoir provides the buffer ca-

pacity to meet the demand during peak period. Allows for leveling out the pumping

demands by allowing the pumping system to ﬁll the reservoir to a speciﬁc level after

which the pumps are shut off, and water is drawn from the reservoir until the level

drops to a predetermined point at which time the pumps restart.

3. Providing ﬁre ﬁghting demand which may account for as much as ﬁfty percent of

total storage. In addition, ﬁre-ﬁghting demands must be met during main line breaks,

power outages, and maximum customer demands.

4. Providing a point to blend different water supplies.

5. Providing ability to supply water during power outages and during maintenance of

transmission mains.

6. Providing the detention time for chlorine disinfection to meet the water quality re-

quirements.

• There are four basic type of storage reservoirs:

1. Underground reservoir

2. Ground level reservoir

3. Elevated reservoirs which include elevated tanks and standpipes

4. Hydropneumatic tanks which are tanks which contain 1/3 air and 2/3 water. The air

in the tank is compressed as the tank ﬁlls with water and the pressurized air pushes

228

Chapter 8. Water Distribution

water out of the tank.

•

Typical material of construction include welded and bolted steel and cast-in-place and

pre-stressed concrete. Some smaller tanks such as the hydropneumatic tank is made from

ﬁberglass.

Newly-installed distribution reservoir or distribution reservoir that has been taken out of

service for repair or inspection is required to be disinfected and sampled for bacteriologi-

cal quality in accordance with the American Water Works Association Standard C652-02.

If the results of the bacteriological sampling are positive for coliform bacteria, the reser-

voir shall be re-sampled for bacteriological quality and the test results shall be submitted to

the State Board for review and approval before the reservoir is placed into service.

Figure 8.2: Typical reservoir piping

8.4 Valves used in Water Distribution

• Valves are a critical component of every water systems.

• Main type of valves used in the water distribution system include:

1. Flow control and isolation valves

2. Air valves

3. Backﬂow prevention valves

• Valves can be classiﬁed based upon the movement of the closure element as:

1. Rotary valve:

– The stem modes from fully open to fully closed position by rotating 90 degrees.

– Rotary valves include: plug, ball and butterﬂy valves.

2. Linear valves:

–

Also known as multi-turn valves, these have a sliding-stem design that pushes a

closure element into an open or closed position.

– Linear valves include: globe, gate and check valves.

– They offer ﬂow control capabilities.

• Valves are used for the following applications:

– Flow and pressure regulation

8.4 Valves used in Water Distribution

229

– System isolation

– Air relief

– Backﬂow or cross-connection prevention

– Pressure reducing and pressure sustaining

–

Controlling levels and preventing overﬂow in elevated tanks and standpipes - Alti-

tude valves

–

Blowoff and drain valves for removing accumulated sediments from low spots and

for dewatering lines and reservoirs.

– Controlling level of water in tanks and activating controls - Float valves

8.4.1 Flow Control and Isolation Valves

• These valves are used for controlling ﬂows or for isolation of pipelines.

•

Valve selection is based upon the application elements including size of pipe and water

pressure.

•

Tables 8.4 and 8.5 summarize the properties and use of the commonly used distribution

system valves.

Globe Valve

Use

• Linear stroke type valve

• Has a spherical shape of valve body.

•

Globe valves have higher pressure drops in comparison to

other valves.

Used for ﬂow and pressure control in large size applica-

tions and for isolation in small sizes.

The torturous path of the ﬂow through a globe valve causes

a larger pressure drop compared to other valves.

An altitude valve is a type of a globe valve, is used for

controlling the level of water in a reservoir. It opens and

closes to ﬁll a high-level tower or tank hydraulically and it

functions by sensing the static level of water in the tower.

•

Globe valves have a movable closure that moves up and down inside of the

valve body.

• Valve body is divided into two halves by a partition or bafﬂe.

•

A small horizontal disc or plug is the closure member which can move up and

down attached to the stem, thus opening or closing the valve.

The discs in contact with the seat closes the valve. The seat can be damaged

by formation of solid deposits. Hence globe valves are suitable only for clean

service.

•

Plug Valve

Use

• The plug valve is the simplest of all valves.

• Rotary stroke type valve

•

The movable closure has a hole through which water is

permitted to pass.

•

Valves have a cylindrical or conically tapered "plugs" which can be rotated

inside the valve body to control ﬂow through the valve.

• A1/4 turn turns the valve from open to closed.

•

The plugs in plug valves have one or more hollow passageways going sideways

through the plug, so that ﬂuid can ﬂow through the plug when the valve is open.

•

Commonly used as the isolation valves on the customer

service lines Corporation Stops.

Gate Valve

Use

• Main application in to isolate sections of mains

• Linear stroke type valve

•

Gate valves are mostly used with larger pipe diameters

(from 2" to the largest pipelines) since they are less com-

plex to construct than other types of valves in large sizes.

Gate valves should not be used to throttle ﬂow as the high

velocity of water through a small valve opening can cause

cavitation and scour damage to the valve.

•

A gate valve, also known as a sluice valve, is a valve that opens by lifting a

barrier (gate) out of the path of the ﬂuid.

Gate valves require very little space along the pipe axis and hardly restrict the

ﬂow of ﬂuid when the gate is fully opened.

The gate faces can be parallel but are most commonly wedge-shaped (in order

to be able to apply pressure on the sealing surface).

•

Table 8.4: Flow control and isolation valves - Table 1 of 2

Butterﬂy Valve

Use

•

Butterﬂy valves offer some restriction to ﬂow, which

increases headloss.

• Rotary stroke type valve

•

Butterﬂy valves are a family of quarter-turn rotational motion valves that are

used in pipelines to shut-off ﬂow.

However, they are much easier to open and close in large

lines than gate valves.

• The butterﬂy valve is not 100 % watertight when closed.

Typically used as a shut-off valve and not for regulating

ﬂow.

• The butterﬂy valve has a disc gate to stop or throttle ﬂuid ﬂow.

• When closed, the disc seats against a rubber-like seal set into the valve body.

•

In the closed position, the disc blocks the valve bore while in the open position,

the disc is oriented perpendicular to the ﬂow direction to allow ﬂow.

Ball Valve

Use

• Rotary stroke type valve

• Typically used as a shut-off valve.

•

Water ﬂow is controlled through a rotational ball containing a hole through its

centre placed in the middle of the valve.

When the ball’s hole is parallel to the water inlet, water can ﬂow through. When

the hole is rotated a quarter turn - 90^◦to the pipe the passage is blocked, and

water cannot ﬂow through.

•

Ball valves are durable, performing well after many cycles,

and reliable, closing securely even after long periods of

disuse.

Foot Valve

Use

• Linear stroke type valve

•

While the pump is running, there’s a constant column of water in the pipe as a

result of the suction that’s created. But when the pump is shut off, the suction

disappears, the water will ﬂow downward through the pipe because of gravity,

back to its original source. The pipe would be left empty of water, instead ﬁlled

with air.

•

Foot valves are used for suction lift applications, like a

well pump. help keep a pump primed therefor stopping

your pump from burning out.

•

Foot valve is a check valve which helps prevent draining of the pump suction

pipe after the pump is turned off keeping the pump primed.

Foot valves open in one direction and close off when the direction of ﬂow is

reversed. That means that in an application such as pumping from a well, the

water can only be extracted out of the well.

Table 8.5: Flow control and isolation valves - Table 2 of 2

232

Chapter 8. Water Distribution

8.4.2 Air Valves

• Air valves are an essential component of the water supply system

•

Air and vacuum formed in water mains may lead to serious operating problems and even

some dramatic consequences. Air can enter piping systems in several ways:

–

Empty Pipelines: Pipelines not in operations are occupied with air. Most of it is

evacuated during startup, but some air pockets can remain in the system.

Dissolved air in water: Depending on the temperature and pressure, water can con-

tain trapped or dissolved air. During ﬂuid ﬂow, it separates from the liquid and can

become trapped at the system’s high points. Also, in pipelines conveying sewage,

the liquid waste can undergo chemical reactions and evolve into gases that can get

trapped in the wastewater system.

–

Mechanical equipment: Air can also get into the pipeline through mechanical sys-

tems like pumps, pipe joints, valves, etc. Leaks or faulty seals in these components.

• Consequences of air and vacuum in pipelines include:

–

Reduced pumping efﬁciency: Air in pipelines can reduce the efﬁciency of the pump-

ing system. The air trapped at the high points of the system blocks ﬂow, increasing

the pressure head and thus the energy required for ﬂow to occur.

Pipeline corrosion: Depending on the pipeline’s temperature, oxygen in the trapped

air can be a powerful corrosive agent. The oxygen oxidizes the metal gradually,

which leads to rusting, blockage, and structural failure of the pipe.

Faulty metering and instrumentation devices: Air pockets and vacuums can cause

problems for ﬂow measuring and control devices. They affect the ability of the de-

vices to accurately measure and control the ﬂow.

Air hammer: When a trapped air pocket is present in a pipe, pressure builds up

around the blockage. The pressure of the water swirling around this blockage sends

vibrations throughout the pipe. This vibration, known as an air hammer, can poten-

tially damage the distribution system components.

–

Pipe failure: Vacuums can cause catastrophic failures in pipelines. If there is a sub-

stantial vacuum, the pipe can collapse inwards due to the pressure difference on both

sides of the pipe’s walls.

•

Table 8.6 summarizes the properties and use of the commonly used distribution system air

valves and Figure 8.3 provides a schematic of the air valve applications.

Air and vacuum valves

• These ﬂoat operated valves allow the escape of air while the line is being ﬁlled.

Use

•

Once the line is ﬁlled, the pressure in the valve keeps the valve from opening

even if air accumulates in the valve.

When the line is drained and the internal pressure drops below atmospheric, the

valve opens, allowing air in preventing a vacuum and possible pipeline collapse.

• Exhausts large quantities of air at system start-up.

• Provides pipeline vacuum protection.

•

Admits large quantities of air to prevent loss of pressure

during power failures, line breaks and drainage

• These valves are also referred to as air relief valves.

Air Release Valve

Use

•

Air is from: the pipeline itself, air dissolved in the water

pumped and drawn in from equipment like pumps, joints

etc.

Prevents pressure surges, water hammer and prevent ﬂow

stoppage due to air binding.

Automatic air release valves are installed at the highest points in a pipeline where air

naturally collects. Air bubbles enter the valve and displace the liquid inside, lowering

the liquid level. When the level drops to where it no longer buoys the ﬂoat, the ﬂoat

drops. This motion pulls the seat away from the oriﬁce, triggering the valve to open and

vent the accumulated air into the atmosphere.

Combination Valves

Use

• There are two types of combination valves.

1. The most common is the combination of air release and vacuum relief

often referred to simply as an air vac valve.

2. The second combination valve is one designed with two oriﬁces, one for

high airﬂow and one for low airﬂow.

•

Gate valves are used to shut off the ﬂow of liquids rather

than for ﬂow regulation.

Gate valves are mostly used with larger pipe diameters

(from 2" to the largest pipelines) since they are less com-

plex to construct than other types of valves in large sizes.

•

Combination air vac valves are installed at high points in the line to allow air in

and out of the line to reduce problems due to a blockage by air.

Allowing air when the line may be being emptied prevents the low internal

pressure from drawing a joint gasket into the pipe and thus causing a leak..

Table 8.6: Air valves in water system

Figure 8.3: Summary of air valve applications

8.4 Valves used in Water Distribution

235

8.4.3 Backﬂow Prevention

•

Backﬂow means the undesirable reversal of ﬂow of a liquid, gas, or suspended solid into

the potable water supply.

• A backﬂow preventer is designed to keep this from happening.

Points at which a potable water system connects with a non-potable water system are

•

called cross connections. Such connections occur naturally in appliances such as clothes

washers and dishwashers, but they must be carefully designed and installed to prevent

backﬂow.

• Back-siphonage :

This is when higher pressure ﬂuids, gases, or suspended solids move to an area of

–

lower pressure ﬂuids. A signiﬁcant drop of pressure in a water delivery system cre-

ates a similar suction, pulling possibly undesirable material into the system. The

effect is similar to drinking water through a straw.

– This is an example of an indirect cross-connection .

• Back-pressure :

Occurs when a ﬂuid under a higher pressure from systems like boilers, heat exchang-

–

ing equipment, power washing equipment, ﬁre sprinklers, or pumps enter potable

water piping. This is an example of a direct cross-connection , with undesirable

material being pushed into the system.

•

To reduce the risk of contamination, a backﬂow preventer can be ﬁtted. A backﬂow pre-

venter is also important when potentially toxic chemicals are used, for instance for com-

mercial/industrial descaling of boilers, or when chemical bleaches are used for residential

power washing.

Another common location for a backﬂow preventer is the connection of a ﬁre sprinkler sys-

tem to a water main, to prevent pressurized water from ﬂowing from the ﬁre suppression

system into the public water supply.

• Backﬂow preventers are categorized into three groupings: Assembly, Device or Method.

•

Tables 8.7 and 8.8 summarize the properties and use of the commonly used backﬂow

devices.

Air Gap

• A physical separation between the free-ﬂowing discharge end of a potable water supply pipeline and an open or non-pressure receiving vessel.

• Should not be used in an area with dangerous atmosphere.

•

An "approved air gap" shall be at least twice the diameter of the supply pipe measured vertically above the overﬂow rim of the receiving vessel; in no case less than 1

inch (2.54 cm).

Common Applications - Lethal hazards (raw sewage, recycled water, auxiliary water supply

Atmospheric Vacuum Breaker Assembly (AVB)

•

Also known as the non-pressure type vacuum breaker, it consists of an air inlet valve, a check seat and an air inlet port(s). (.) The ﬂow of water into the body causes the

air inlet valve to close the air inlet port(s).

When the ﬂow of water stops the air inlet valve falls and forms a check valve against backsiphonage. At the same time it opens the air inlet port(s) allowing air to enter

and satisfy the vacuum.

• A shutoff valve immediately upstream may be an integral part of the assembly, but there shall be no shutoff valves or obstructions downstream.

•

An atmospheric vacuum breaker is designed to protect against a non-health hazard (i.e., pollutant) or a health hazard (i.e., contaminant) under a back-siphonage

condition only.

Common Applications - Irrigation systems

Spill Resistant Vacuum Breaker

•

Its assembly consists of an independently operating internally loaded check valve and independently operating loaded air inlet valve located on the discharge side of the

check valve.

The assembly is to be equipped with a properly located resilient seated test cock, a properly located bleed/vent port, and tightly closing resilient seated shutoff valves

attached at each end of the assembly.

• This assembly is designed to protect against a non-health hazard(i.e., pollutant) or a health hazard (i.e., contaminant) under a backsiphonage condition only.

Common Applications - Irrigation systems

Swing Check Valve

•

Its assembly consists of an independently operating internally loaded check valve and independently operating loaded air inlet valve located on the discharge side of the

check valve.

The assembly is to be equipped with a properly located resilient seated test cock, a properly located bleed/vent port, and tightly closing resilient seated shutoff valves

attached at each end of the assembly.

• This assembly is designed to protect against a non-health hazard(i.e., pollutant) or a health hazard (i.e., contaminant) under a backsiphonage condition only.

Common Applications - Irrigation systems

Table 8.7: Backﬂow prevention devices - Table 1 of 2

Double Check Valve Assembly

•

Its assembly is composed of two independently acting, approved check valves, including tightly closing resilient seated shutoff valves attached at each end of the

assembly and ﬁtted with properly located resilient seated test cocks.

• This assembly is used to protect against a non-health hazard (i.e., pollutant)

Common Applications - Fire sprinkler systems, non-hazardous irrigation, combi-boilers, non-health hazards

Reduced Pressure Zone Assembly

• This assembly includes two independently acting check valves and an intermediate relief valve that opens to the atmosphere if both check valves should fail.

• Also includes properly located resilient seated test cocks and tightly closing resilient seated shutoff valves at each end of the assembly.

• This is considered suitable for signiﬁcant hazard applications that is, where the consequence of backﬂow into the water supply would cause signiﬁcant harm.

• They are considered suitable because they prevent both back pressure and back-siphonage,

• Its redundant design allows it to provide protection even with two check valves broken

• This assembly is not for backﬂow protection of sewage or reclaimed water.

Common Applications – Domestic water and irrigation service protection, health hazards

Table 8.8: Backﬂow prevention devices - Table 2 of 2

238

Chapter 8. Water Distribution

8.5 Fire Hydrants

•

Fire hydrants is a visible connection pint in the water distribution system to provide water

at a high ﬂow rates primarily for:

– Fire ﬁghting

– Flushing distribution systems

– For other utilities, such as street cleaning and sewer cleaning

• Hydrants can be categorized as:

– Wet barrel

Have the operating valve in the nozzle section of the hydrant and are operated by

rotating the operating stem on each of the outlets.

These hydrants are used in warm climates where it rarely freezes.

Their main advantage is the ease of connecting a second ﬁre truck.

Each discharge port is independently valved.

– Dry barrel

These have the operating valve installed below ground.

The hydrant is equipped with a special drain valve that allows the above ground

portion to automatically drain when not in use.

The dry barrel hydrant is widely used in colder climates.

Its main advantage is that it is less likely to freeze and normally not loose water

when hit by a vehicle.

The dry-barrel hydrant must always be opened completely and never partially

as the partially opened hydrant will allow pressurized ﬂow through the drain

valve, which may wash away the soil from the area surrounding the base, or

the partially open main valve may trap small stones or other debris between the

valve seal and seat.

Figure 8.4: Types of ﬁre hydrants

8.6 Water Meters

239

•

A ﬂush hydrant sits ﬂush with the surface of the ground and is used in airports, on bridges,

and other places where the exposure of the hydrants is more of a hazard than the difﬁculty

of connecting to a ground-level hydrant.

8.6 Water Meters

•

Meters measure, display, and record the amount of water that passes through a distribution

system component.

• Typical applications of meters in a distribution network include:

– Measuring the amount of water supplied to the system.

–

Measuring the amount of water supplied to a particular area of the system, including

through a pump station or control valve.

– Measuring the amount of water used by a customer, for billing purposes.

– Monitoring unaccounted-for water in a distribution network.

Table 8.9 summarizes the properties and use of the commonly used distribution system

water meters.

•

240

Chapter 8. Water Distribution

Positive Displacement (PD) Meter

•

Nutating disc ﬂow meter is the most common types of PD ﬂow me-

ter. A disc mounted to a central ball wobbles (nutates) when ﬂuid

enters the chamber, transferring the displaced volume to the register.

• Commonly used as customer service meters.

• Typically has a diameter of 2-inches or less.

• Generally used to measure low ﬂow rates.

• Have limitations at very high ﬂows.

Velocity Meter

•

Commonly used in pump stations, industrial facilities, and large

diameter mains to measure high rates of ﬂow.

• Does not accurately measure low ﬂow rates.

• Includes the Venturi, Turbine, and Propeller type meters.

Compound Meter

•

Commonly used to measure ﬂow at apartment complexes, schools,

and industries that can typically have high peaks in water use com-

pared with daily averages.

• Composite of the displacement and velocity meters.

• Used to measure ﬂowrates that vary widely.

Electronic Meter

• Measures ﬂow magnetically (mag meter) or sonically.

• Highly accurate if properly located.

Proportional Meter

• Measures high ﬂowrates at larger pipes such as ﬁre service lines.

•

It has a small bypass meter, located parallel to the main pipe which

is calibrated to measure the ﬂow through the main pipe.

• Does not measure low ﬂows accurately.

Table 8.9: Types of water meters

8.7 Distribution System Operation and Maintenance Elements

241

8.7 Distribution System Operation and Maintenance Elements

8.7.1 Maintaining distribution system pressure

•

Distribution systems must be maintained under pressure at all times to help ensure that

contamination does not enter the system.

•

In the event that the distribution system is de-pressurized, the water system operator must

promptly restore pressure and take corrective action to monitor and restore water quality.

The corrective action should include ﬂushing and disinfection.

8.7.2 System Disinfection Program

Disinfecting New and Existing Wells

Well disinfection under the following circumstances should be performed in accordance with

the American Water Works Association C654-03, and re-sampled for bacteriological quality and

the test results shall be submitted to the State Board for review and approval before the well is

placed into service:

• A new or repaired well, or a well that has not been in operation for more than three months

• When coliform bacteria are present in the water

• After ﬂooding of the well

• After plumbing installation, e.g. softeners, sinks, ﬁlters

• After casing or pump repairs - submersible types or other

• When water taste or odor changes, e.g. from iron or sulfur reducing bacteria

• As part of annual maintenance

• During startup of seasonal wells

• Elements of well disinfection include:

– Disinfection is accomplished using sodium hypochlorite

– A 50 mg/l chlorine concentration is recommended with a 24-hour contact time

–

Application of bleach through the pump column pipe is preferred over the application

using the vent pipe as the chlorine injection point.

–

At the end of the disinfection period, the well is pumped until all evidence of residual

is gone.

Disinfecting Water Mains

•

Disinfection of repaired mains is not required, if the repairs are done with the line full of

water and under pressure.

• Utmost care should be taken to prevent contamination during installation or repairs

• Valves and ﬁttings must be cleaned during installation.

•

Sections of pipes, ﬁttings and valves and other items that will not be disinfected by the

ﬁlled line must be precleaned and disinfected.

•

Prior to use, newly installed water mains, or water mains that have been taken out of ser-

vice for maintenance or repair, shall be disinfected and sampled for bacteriological quality

in accordance with American Water Works Association Standard C651-05.

242

Chapter 8. Water Distribution

•

Crushed HTH tablets be placed in joints and hydrant branches to improve disinfection of

spaces that are difﬁcult to chlorinate once ﬁlled with water.

Flushing the mains for atleast 30 minutes at a minimum velocity of 2.5 ft/sec is recom-

mended prior to disinfection

• Common methods for disinfecting water mains are:

CHLORINATION MAXIMUM MINIMUM CON- MINIMUM

METHOD

CHLORINE

TACT TIME, HR

CHLORINE

DOSAGE, mg/l

RESIDUAL, mg/l

Continuous

Slug

500

300

Tablet

• Post-disinfection, lines must be ﬂushed until chlorine residual is less than 1 mg/l

•

Bacteriological test - 24-hour membrane ﬁlter test is required to be conducted after disin-

fection and prior to placing the line in service.

8.7.3 Disinfecting Water Storage Tanks

•

After the repair/rehabilitation of the water tank is conducted or after the construction of the

new tank, prior ot putting the tank in-service, the surfaces of the walls, ﬂoor, and operating

facilities of the storage facility shall be cleaned thoroughly by use of a high pressure water

jet, sweeping, scrubbing, or equally effective means.

•

After the cleaning, the tank is required to be disinfected and is deemed adequately dis-

infected and ready for service only if the bacteriological testing results show negative

coliform results.

AWWA C652-19 Disinfection of Water Storage Facility is the standard for disinfection of

water-storage facilities describes materials, facility preparation, application of disinfectant

to interior surfaces of facilities, and sampling and testing for the presence of coliform

bacteria, chlorine residual, and acceptable aesthetic water quality.

• Acceptable water storage disinfection procedures include:

1. A new tank can be disinfected by ﬁlling the tank to the overﬂow level with potable

water with an initial chlorine concentration of 50 mg/L in the full tank and holding

that water for 24 hours.

2. Application of a chlorine solution containing at least 200 mg/L of free available

chlorine using either spray equipment or brushes followed by keeping the chlorine

solution in contact with the tank surfaces for at least 30 minutes. The tank is then

ﬁlled with the distribution system water that is treated with chlorine to provide a

residual of atleast 3 mg/l and held for 3-6 hours.

•

After the disinfection step is completed, the tank is ﬁlled with potable water to the over-

ﬂow level and tested for satisfactory bacteriological quality before placing the tank in

service.

For the bacteriological testing, two water samples from the tank are to be collected at least

8.7 Distribution System Operation and Maintenance Elements

243

24 hours apart and analyzed by a certiﬁed laboratory. The results of these samples must

indicate no coliform contamination before the pipe, tanks, or equipment can be utilized as

part of the water distribution system.

8.7.4 System Flushing Program

•

Each public water system should ﬂush the water distribution system as necessary to reduce

stagnant water and sediment build-up.

• Flushing is normally practiced after receiving water quality complaints.

•

Advance planning elements include: minimizing inconvenience to customers and trafﬁc

impacts, public notiﬁcations, identifying sections of mains to be ﬂushed and required

valving and resource allocations.

•

Unidirectional ﬂushing - where the ﬂushing start point is at or near the source of supply

and working outward into the distribution system is usually practiced.

• A minimum ﬂushing velocity of 2.5 ft/sec is recommended.

• Hydrants are opened for atleast 5 to 10 minutes to stir up deposits.

•

Usually lines are ﬂushed for atleast 30 minutes while ensuring the system pressure of the

affected area does not drop below 20 psi.

Water samples may be taken at the beginning ad after ﬂushing to determine its effective-

ness and to identify need for additional ﬂushing.

8.7.5 Valves Operation and Maintenance

• Hydraulic problems associated with improper operation of valves include:

– Cavitation

Cavitation is a common occurrence in valves used in throttling or modulating

service during the last few degrees of closure when the supply pressure is greater

than about 100 psig.

Cavitation is the sudden vaporization and violent condensation of a liquid down-

stream of the valve due to localized low pressure zones.

When ﬂow passes through a throttled valve, a localized low pressure zone forms

immediately downstream of the valve. If the localized pressure falls below the

vapor pressure of the ﬂuid, the liquid vaporizes (boils) and forms a vapor pocket.

As the vapor bubbles ﬂow downstream, the pressure recovers, and the bubbles

violently implode causing a popping or rumbling sound similar to tumbling

rocks in a pipe.

The sound of cavitation in a pipeline is unmistakable.

Cavitation can quickly destroy valve internals and even erode through pipe

walls.

The condensation of the bubbles not only produces a ringing sound, but also

creates localized stresses in the pipe walls and valve body that can cause severe

pitting.

244

Chapter 8. Water Distribution

Cavitation may be prevented by ensuring selection of right size, type and loca-

tion of the valve.

Figure 8.5: Valve Cavitation

– Water Hammer

Water hammer is the result of a pressure surge, or high-pressure shockwave that

propagates through a piping system when a ﬂuid in motion is forced to change

direction or stop abruptly.

This shockwave is typically characterized by a marked banging or knocking

sound on the pipes immediately after a shutoff.

Water hammer can occur when an open valve suddenly closes, causing the wa-

ter to slam into it, or when a pump suddenly shuts down and the ﬂow reverses

direction back to the pump.

Since water is incompressible, the impact of the water results in a shock wave

that propagates at the speed of sound between the valve and the next elbow in

the piping system or within the column of water after the valve.

Water hammer, like cavitation, has the potential to cause catastrophic destruction

to the distribution system piping.

Selecting the correct valve and lengthening the valve closure duration help miti-

gate water hammer occurrence.

•

Valves must be maintained in working order. This necessitates that valves be “exercised”

on a routine basis and visually inspected for leaks on a regular basis.

• Valve information including the following should be readily available:

– System map showing valve locations and system isolation points

–

Information on valve sizing, direction to open the valve, number of turns, model type

and installation date

•

Adequate inventory of valves and its replaceable parts need to be maintained to ensure

availability .

Detailed records of valve inspections and maintenance activities including inspection logs

and service requests must be maintained.

8.7 Distribution System Operation and Maintenance Elements

245

8.7.6 Distribution System Map

•

Each water system should maintain an accurate map of the distribution system piping and

valves.

The map should be sufﬁciently detailed to enable maintenance personnel to promptly

locate facilities for repair or operational purposes.

All valves and pipes are shown on the system’s "as built" plans. They are updated as re-

pairs are made. In addition, the ﬁxed facilities and structures are shown on the map.

• Comprehensive and plat maps are typically used.

• A comprehensive map provides an overall view of the entire distribution system.

•

A plat map shows property boundaries and includes roads and location of utilities such as

gas lines, access by water and sewer lines, as well as the location of buildings and other

infrastructure on the property.

•

A map scale which is distance on the map and distance on the ground (actual), allows for

showing locations and distances accurately on a sheet of paper of convenient size

A map scale is provided on the map as a fraction or a ratio-1/10,000 or 1:10,000. These

"representative fraction" scales mean that one unit of measurement on the map 1 inch or 1

centimeter represents 10,000 of the same units on the ground.

•

The scale used will be dependent on the size of system and the size of the map. A com-

monly used scale for maps used for utilities is 1:600 - 1-inch on the map represents 600

inches or 50 feet (600 feet * 12inches/1 feet) on the ground.

8.7.7 Distribution System Record keeping

The minimum record keeping requirements include:

• Date, time and cause of any system pressure loss.

• Corrective action taken in response to system pressure loss.

• Distribution system repairs and maintenance: date, location and reason for repairs.

8.7.8 Water Usage Records

•

Each public water system should have production meters and should maintain records on

water usage throughout the year. These records are kept for future information.

8.7.9 Storage Tank Maintenance

Water storage tanks should be inspected on a regular basis to ensure that the structure is in

satisfactory condition and properly secured.

•

• Records should be maintained of these inspections.

• Access hatches should be locked and all openings to the tank should be properly screened.

• Roofs should not allow entry of contaminants.

•

The storage tank is visually inspected weekly. A detailed inspection is done on the tank

every four (4) months.

246

Chapter 8. Water Distribution

•

Applying protective coating - painting/coating, the internal and external walls of the tank

needs to be conducted periodically.

• Several tank coating related considerations and precautions include:

–

Selecting the right paint - paints containing lead, PCBs, trichloroethylene etc. should

be avoided.

–

Ensuring appropriate surface preparation and adequate coatings drying times are

provided.

• Periodic, visual inspections and detailed cleaning and internal inspections are required.

• Records of the inspections are kept and any problems noted.

8.7.10 Lead and Copper Sampling

1. Samples are collected at customer’s tap usually by the customer.

2. Sample needs to be a ﬁrst draw sample - not allowing the water to run and NOT ﬂushing

out the service line.

3. Sample is collected early in the morning - no water to be used for a minimum of six hours

before a sample is collected, no ﬂushing and no opening a faucet.

4. Samples are not be be collected from unoccupied home where water has not been used for

over 24 hours.

5. Action level for lead is 0.015 mg/L and copper is 1.30 mg/L

6. Action level means entailing either service line replacement program or changing water

quality parameters, or adding chemicals such as polyphosphate to the water to reduce its

corrosion potential.

8.7.11 Computer Based Controls and Monitoring

1. SCADA

•

SCADA - Supervisory Control and Data Acquisition is a useful and now widely used

computer based control system

•

Distribution system components and operational parameters including - pressures,

ﬂows, meters, pump speed, wetwell levels, valve positions etc. can be monitored and

controlled onsite or from a central location using SCADA.

•

SCADA allows for monitoring system operations to identify excursions of operat-

ing equipment from normal operating conditions/ranges and help predict/identify

maintenance, repair and replacement requirements.

2. Automated Meter Reading

•

Automated Meter Reading (AMR) is the communication technology water utilities

use to automatically collect water consumption and status data from water meters.

After collection, the meter data is transferred to a database where utilities can mon-

itor and analyze usage, troubleshoot issues and bill customers based on actual con-

sumption, rather than predictions that were often required with bi-monthly or quar-

terly manual reads.

•

8.7 Distribution System Operation and Maintenance Elements

247

3. Advanced Metering Infrastructure

•

Advanced metering infrastructure (AMI) is an integrated system of water meters,

communication networks and data management systems that enables two-way com-

munication between meter endpoints and utilities.

•

The utility can use the data to improve operational efﬁciencies and sustainability by

effectively monitoring water usage and system efﬁciency, detecting malfunctions and

recognizing irregularities.

8.7.12 Corrosion Control

•

Metallic elements of the water distribution system, including pipes and ﬁttings, is subject

to corrosion where the metal is converted to its salt or oxide.

• Corrosion in the water distribution system leads to:

–

Reduced mechanical strength leading to a loss in service life and piping failures -

leaks and ruptures.

– Leaching of toxic metals such as lead and copper into the drinking water

–

Formation and deposition of corrosion by-products in pipes made from material

which include iron, leading to:

Desposition of corrosion products on the inside surface of the pipe - Tuber-

culation increase the roughness of the pipe, increasing the resistance to water

thereby decreasing the water carrying capacity of the pipe and increasing the

pumping cost.

Figure 8.6: Tuberculation

Consumer complaints of reddish or reddish-brown water and staining of plumb-

ing ﬁxtures due to the presence of iron oxides.

• Corrosion can happen from the outside of the pipe and also from the inside.

•

Corrosion from the outside occurs because of either Galvanic Corrosion resulting from

and electric current ﬂowing between two dissimilar metals which are in direct contact or

indirect contact through a conductive environment such as moist soil or due to Chemical

Corrosion due to corrosive soil.

248

Chapter 8. Water Distribution

Figure 8.7: External Corrosion

• Corrosion from the inside occurs because of:

–

Water quality parameters which promote corrosion - low pH (acidic water, less than

7.0, but typically in the range of 4.0 to 6.5), low carbonate alkalinity, high oxygen

content, high total dissolved solids, and/or high chloride or sulﬁdes

Bioﬁlm/slime formed on the inside surface of the pipe by bacteria creates an oxygen

depleted environment under the bioﬁlm next to the pipe surface, which in turn leads

to the growth of speciﬁc types of bacteria that produce by-products corrosive to

metals.

–

• Corrosion control is critical to ensure integrity of the distribution system.

• Corrosion rates are affected by the quality of water and system components design.

• Regular inspections and observations provide indications of corrosion activity.

•

Corrosion coupons placed in the system provide quantitative measurement of corrosion.

Coupons are small pieces of the same type of metal as the piping which are inserted into

pipes at various locations in the distribution system and are left in place for a period of

time after which the amount of metal lost from the coupon due to corrosion can be deter-

mined.

Figure 8.8: Corrosion Coupon

Figure shows how a corrosion coupon is inserted using a transparent pipe

• Other maintenance and operation elements to control corrosion include:

– Ensuring integrity of internal and external coatings of pipes and storage tanks

– Dosing adequate quantities of corrosion inhibitors

8.7 Distribution System Operation and Maintenance Elements

249

– Protecting the piping from external galvanic corrosion by the installation and proper

operation of cathodic protection systems. A cathodic protection system protects a

steel pipe from galvanic corrosion by electrically connecting the pipe to a replace-

able, highly active metal - anode, which looses its ions and keeps the less active steel

pipe from corroding.

Figure 8.9: Cathodic Protection

–

Ensuring adequate secondary disinfection and periodic ﬂushing of lines to minimize

and remove bioﬁlm/slime growth.

Chapter 8 Assessment

1. What is the reason for keeping adequate, reliable records in a treatment plant?

*a. *to record the plant’s effectiveness and because of requirements by regulatory agencies

b. to maintain records for cold cases

c. in case the IRS wishes to check ﬁles for due diligence

d. because of homeland security issues and ﬁles being available to the public

2. Which statement about displacement meters is not correct:

a. The most common type of water service meter is the displacement type

b. Displacement meters are accurate at low ﬂows

c. Excess sediment can cause the meter to stop registering

d. Displacement meters have little head loss due to friction

e. Displacement meters operated at a rate in excess of its stated capacity can result in

excessive wear

3. A ﬁre hydrant should be closed slowly to avoid:

a. Excessive wear

b. Water hammer

c. Excessive head loss

d. Injury to operator

4. The minimum separation between municipal water mains and sanitary sewers for installa-

tion in a common trench shall be:

a. 5 feet horizontal separation

b. 10 feet horizontal separation

252

Chapter 8. Water Distribution

c. 15 feet horizontal separation

d. 25 feet horizontal separation

5. To properly disinfect a water main after new construction, you should:

a. apply 50mg/l chlorine for 24 hours.

b. clean the pipe out’ with a pig and then disinfect at 10mg/1 for 24 hours

c. use a 10% solution of calcium chloride

d don’t use them main for one week

6. When using a dry-barrel ﬁre hydrant, the valve:

a. should never be opened completely

b. be opened only during the hours of 8AM to 5PM

c. be opened to the desired amount of ﬂow

d. be opened all the way

7. The primary reason for dry barrel-ﬁre hydrants is to:

a. allow easy maintenance

b. prevent water hammer

c. keep the hydrant from freezing

d. keep the barrel from rusting

8. A centrifugal pump should not be run empty except momentarily because:

a. a serious counter pressure could develop and damage the pump casing. b. it is a waste of

energy to run a pump without water.

c. the excessive end thrust of the shaft would damage the thrust bearing.

d. the parts lubricated by water could be damaged.

9. Pipes of dissimilar metal should not be connected together because of problems due:

a. to scale formation

b. corrosion

c. water hammer

d. the venturi effect

10. Which type of valve will prevent the collapse of a pipe?

a. Pressure-relief valve

b. Needle valve

c. Pinch valve

d. Air-and-vacuum relief valve

11. The correct protective methods for backﬂow-prevention devices in order of decreasing

effectiveness are

a. air gap, VB, RPZ, and DCVA.

b. air gap, VB, DCVA, and RPZ.

c. air gap, RPZ, VB, and DCVA.

d. air gap, RPZ, DCVA, and VB.

12. The C-value is a measure of a pipe’s wall

a. smoothness.

8.7 Distribution System Operation and Maintenance Elements

253

b. smoothness giving even ﬂow.

c. smoothness that retards turbulent ﬂow.

d. roughness that retards ﬂow due to friction.

13. Which one of the following is a type of joint for ductile iron piping?

a. Expansion joint

b. Push-on joint

c. Bell and spigot with rubber o-ring

d. Rubber gasket joint

14. Water hammer can be described as

a. particle waves.

b. acoustic waves.

c. rogue waves.

d. longitudinal waves.

15. Which thrust control is easy to use, especially in locations where existing utilities or struc-

tures are numerous?

a. Restraining ﬁttings

b. Tie rods

c. Thrust anchors

d. Thrust blocks

16. The backﬁll material for a pipe installation should contain enough to allow for thorough

compaction.

a. moisture

b. sand

c. gravel

d. mixed sizes

17. Thrust from a water surge almost always acts pushes against. to the inside surface that it

a. vertically

b. horizontally

c. perpendicular

d. vertically and horizontally

18. The breaking of a buried pipe when it is unevenly supported is called

a. stress breakage.

b. shear breakage.

c. beam breakage.

d. ﬂexural breakage.

19. Compression ﬁttings used with copper or plastic tubing seal by means of a

a. beveled sleeve.

b. compression ring.

c. compressed beveled gasket.

d. compressed o-rings located at either end of the ﬁtting’s beveled neck.

254

20. Which should be installed at a dead-end water main?

Chapter 8. Water Distribution

a. Vacuum valve

b. Air valve

c. Blowoff valve

d. Water quality sampling station

21. First draw samples for the analysis of lead and copper water must be collected from taps

where the water has stood motionless in the plumbing for at least

a. 4 hours.

b. 6 hours.

c. 8 hours.

d. 24 hours.

22. According to AWWA Standard C651, disinfection of water mains requires 24-hour expo-

sure to which minimum free chlorine residual?

a. 10mg/L

b. 25mg/L

c. 50mg/L

d. 100mg/L

23. The tensile strength of a pipe is its ability to

a. Stretch or pull without breakage

b. Resist internal pressure without breakage

c. Resist external pressure without breakage

d. Twist or bend without breakage

e. Resist heating without breakage

24. The lowest point of the inside of a pipe is known as the

a Pervert

b. Sofﬁt

c. Invert

d. Curb stop

e. None of the above

25. A lightweight type of pipe that has a very smooth interior, is essentially corrosion-free, and

which is difﬁcult to locate when buried is

a. Polyvinyl chloride

b. Cast iron

c. Ductile iron

d. Concrete cylinder

e. Steel

Chapter 9

9.1

9.2

9.3

Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

Hazard Control Approaches

Water Treatment Hazards

Safety Practices

9. Safety

Expected Range of Knowledge for Safety

Water Distribution System Operator License Exams

Knowledge of OSHA/Cal-OSHA safety regulations

Knowledge of the components of the Emergency Response Plan

Knowledge of Cal-OSHA trenching and shoring requirements

Ability to recognize a conﬁned space

Knowledge of chemical handling safety equipment and procedures

Knowledge of conﬁned space safety equipment and procedures

Knowledge of electrical safety equipment and procedures

Knowledge of ﬁre safety equipment and procedures

Knowledge of hazardous material safety equipment and handling

Knowledge of personal safety equipment and procedures

Knowledge of safety regulation requirements (e.g. IIPP)

Knowledge of the elements of a safety program (e.g. policy statement, training, promotion,

accident investigation, reporting)

Knowledge of trafﬁc control procedures

Knowledge of trenching safety equipment and procedures

Knowledge of safety equipment requirements

Knowledge of recordkeeping/reporting requirements to OSHA

Ability to develop and implement a safety plan

258

Expected Range of Knowledge for Safety

Chapter 9. Safety

Water Treatment Operator License Exams

Ability to demonstrate safe work habits

Ability to identify potential safety hazards

Ability to recognize unsafe working conditions

Ability to select and utilize safety equipment

Knowledge of compressed gas safety procedures

Knowledge of conﬁned space safety procedures

Knowledge of electrical safety

Knowledge of hazardous chemical handling

Knowledge of incompatible chemicals

Knowledge of lock-out/tag-out procedures

Knowledge of Material Safety Data (MSD) sheets

Knowledge of personal protective equipment (PPE)

Knowledge of proper chemical handling techniques

Knowledge of safe working practices

Knowledge of the use of safety equipment

Knowledge of HAZWOPER guidelines

Ability to generate a written safety plan

9.1 Hazard Control Approaches

259

9.1 Hazard Control Approaches

•

Treatment plant operators face a variety of workplace safety hazards ranging from physical

injuries to hazardous material exposure.

• The three principal approaches for hazard control are:

1. Engineering Controls: Engineering controls include incorporating safety elements

during engineering design and include considerations related to selecting a less haz-

ardous alternatives, establishing physical barriers and elements related to ventilation.

2. Administrative Controls: Administrative controls are used to improve safety within

the workplace by putting in place policies and rules that reduce the occupational risk

faced by workers via altering the way their work is performed. These include: house-

keeping, materials handling and transfer procedures, training, providing facilities to

support personal hygiene practices and medical surveillance.

3. Personal Protective Equipment: Personal protective equipment (PPE)is equipment

worn to minimize exposure to hazards that cause serious workplace injuries and

illnesses. PPE includes respiratory protection and protective clothing - hard hats,

safety glasses/goggles, work gloves, chemical resistant gloves and safety shoes.

•

The Occupational Safety and Health Administration OSHA , a. Federal Government

agency is responsible for establishing and enforcing workplace safety and health regula-

tions.

9.2 Water Treatment Hazards

9.2.1 Hazardous Chemicals

•

Hazardous chemicals are used throughout water treatment plants and in distribution sys-

tems.

•

To understand the dangers of these chemicals and to take adequate steps OSHA requires

that the chemical manufacturer, distributor, or importer provide Safety Data Sheets (SDSs)

(formerly MSDSs or Material Safety Data Sheets) for each hazardous chemical to down-

stream users to communicate information on hazards related to that particular chemical or

product.

•

Employers must ensure that the SDSs are available and readily accessible to employees for

all hazardous chemicals in their workplace.

• The SDS includes information such as the properties of each chemical; the physical, health,

and environmental health hazards; protective measures; and safety precautions for han-

dling, storing, and transporting the chemical.

•

OSHA’s Hazardous Waste Operations and Emergency Response (HAZWOPER) standards

aims to prevent and minimize the possibility of worker injury and illness resulting from

potential exposures to hazardous substances. It requires that employers follow speciﬁc

work policies, practices, and procedures to protect their workers potentially exposed to

hazardous substances.

260

Chapter 9. Safety

Effects of Chemical Hazards

Hazardous chemicals can cause:

• Headaches, rashes and burns

• Respiratory problems

• Lung and liver damage

• Reproductive damage

• Cancer

• Death

Protection from chemicals

Chemical manufacturers, distributors, or importers are required to provide Safety Data Sheets

(SDS) (formerly MSDSs or Material Safety Data Sheets) for each hazardous chemical to down-

stream users to communicate information on these hazards.

• Reading and understanding the associated Safety Data Sheets

• Wearing appropriate Personal Protective Equipment

• Implementing safe work practices by:

–

NEVER: Eating, drinking or smoking when working with hazardous chemicals, and

washing or storing PPE with personal clothing.

–

ALWAYS:Washing hands, arms and face with soap and water after use, ensuring

integrity of PPE before and after use and also very importantly ensuring readiness to

deal with chemical exposure or spill.

OSHAs SDS Guidance Document provides detailed information on the structure and contents.

This document is provided in Appendix F.

A sample SDS is provided in Appendix G.

9.2 Water Treatment Hazards

261

Ensuring chemicals storage compatibility

Storing incompatible chemicals together could create a hazardous reaction such as the produc-

tion of toxic gas, accelerated corrosion, or an exothermic reaction - reaction that releases heat,

potentially resulting in an explosion and/or ﬁre.

9.2.2 Falls

•

Falls are one of the leading causes of injuries and deaths on the job. Fall protection is a

combination of methods and devices used to protect workers from falling off, onto, or

through working levels.

•

Working on top of tanks, walkways roofs, and other elevated surfaces more than 4 feet

or when working above open tanks or hazardous machinery requires the provision of fall

protection.

•

Fall protection methods and devices are typically divided into two categories: those that

prevent falls and those that arrest falls.

Examples of fall protection methods and devices include rails, guards, guardrails, barriers,

fall-arrest systems, safety nets, hole covers, and various work practices and procedures.

9.2.3 Noise

• Noise as a hazard is sound that is especially loud or impacting.

•

A wastewater treatment plant has equipment that produces high noise levels both continu-

ously and intermittently.

•

As such, it is important to be aware of this hazard and to take preventive steps to reduce

exposure to damaging noise levels by wearing effective hearing protection and to minimize

the duration of the exposure to the noise.

9.2.4 Electrical Hazards

Ordinary 120-V electricity can be fatal; most wastewater facility electrical systems operate

at 120 to 4000 V or more.

• All voltages should be considered dangerous and potentially life threatening.

•

262

Chapter 9. Safety

•

Safe working rules and practices that should be followed when working on electrical sys-

tems

Before working on an electrical system, perform a job hazard analysis to determine any

potential hazards and methods of abating those hazards

9.2.5 Trenching & Excavation Hazards

• Trench collapses, or cave-ins, pose the greatest risk to workers’ lives.

•

Potential hazards related to trenching include: falls, falling loads, hazardous atmospheres,

and incidents involving mobile equipment including vehicular trafﬁc.

A good rule of thumb is to slope the sidewalls at least one and one half foot back for every

one foot in depth on both sides of the trench unless the soils have been classiﬁed as to the

type and the options provided in the OSHA Standard have been selected by a competent

person.

•

For excavations greater than 4 feet, potential for hazardous atmospheres must be consid-

ered. If the environment has the potential for a hardous atmosphere, adequate precautions

need to be taken to prevent worker exposure to those conditions.

Provision for access and egress for personnel as well as equipment is required. Ramps

for access/egress must be designed by a competent person and be capable of handling the

intended loads.

A stairway, ladder or ramp must be provided within 25 lateral feet of employees in trench

excavations greater than 4 feet. Ladders should extend a minimum distance of 3 feet past

the edge they rest against but not more than 4 feet.

•

Trenches 5 feet deep or greater require a protective system unless the excavation is made

entirely in stable rock.

Trenches 20 feet deep or greater require that the protective system be designed by a regis-

tered professional engineer.

• Types of protective systems :

–

Benching - excavating the sides of an excavation to form one or a series of horizontal

levels or steps.

–

Sloping - involves cutting back the trench wall at an angle inclined away from the

excavation. A good rule of thumb is to slope the sides of the excavation to an angle

not steeper than 1½:1 (for every foot of depth, the trench must be excavated back

11/2 feet) excavated back 1½ feet). A slope of this gradation is safe for any type of soil.

Figure 9.1: Trench Slope

–

Sloping and benching consists of the removal of the trench wall at a speciﬁc slope based on

9.2 Water Treatment Hazards

263

the type of soil being excavated.

–

Sheeting - wooden sheets or metal plates are placed against the side of the trench to hold

back the walls. Uprights placed vertically along the face of the trench wall are used to sup-

port the sheeting. Stringers or wales are placed horizontally along the uprights in which

trench braces are attached to prevent cave-in.

–

Shoring - requires installing aluminum hydraulic or other types of supports designed to

support the walls of a trench.

Shielding - uses a two-sided, braced box sometimes referred to as a drag shield or trench box,

which is open at the top, bottom and ends.

Figure 9.2: Trench Protection Systems

•

OSHA standards require, before any worker entry, that employers have a competent per-

son inspect trenches daily and as conditions change to ensure elimination of excavation

hazards.

• Key elements related to ensuring trench safety :

– Ensure that there’s a safe way to enter and exit

– Ensure trenches have cave-in protection

–

Test for atmospheric hazards such as low oxygen, hazardous fumes and toxic gases

when > 4 feet deep.

–

Inspect trenches at the start of each shift and following a rainstorm or other water

intrusion.

– Keep excavated soil (spoils) and other materials at least 2 feet from trench edges.

– Never enter a trench unless it has been properly inspected by a competent person

9.2.6 Rotating and Moving Equipment

• All rotating and moving equipment should be guarded.

•

The best method for preventing machinery-related injuries is through use of equipment

guards enforced through engineering and administrative controls.

264

Chapter 9. Safety

•

The best way to prevent this type of injury is to install point-of-operation guards that pre-

vent contact with nip points, pinch points, rotating parts, ﬂying chips, and sparks.

9.2.7 Heat Stress

• Heat stress falls into two categories: heat illness and heat stroke.

• Both are serious conditions and should not be taken lightly.

• Heat stress can result from:

– High temperature and humidity, dehydration from low ﬂuid consumption

– Direct sun exposure (with no shade) or extreme heat,

– Limited air movement (no breeze or wind),

– Physical exertion, Use of bulky protective clothing and equipment,

– Poor physical condition or ongoing health problems,

– Some medications

– Pregnancy

9.2.8 Material Handling Ergonomics

•

Wastewater operators are potentially subject to risk of musculoskeletal injuries associated

with handling heavy or unwieldy objects including tools and supplies as part of their daily

work routine.

•

The risk and severity of these injuries can be mitigated through utilizing proper ergonomic

techniques which include:

–

Use mechanical means (e.g. hand trucks, pushcarts, etc.) when possible for heavier

or awkward loads.

– It is easier and safer to push than to pull.

–

Keep loads as close to the body as possible and do not twist while lifting, carrying,

or setting down a load. Nose, shoulders, hips, and toes should all be facing the same

direction.

– Minimize reaching.

– As a general rule, bend at the knees, not the hips.

–

Get help when needed. Do not lift or carry things you don’t feel comfortable with, no

matter how light the load.

– Plan ahead for all parts of the lift: lifting, carrying, and setting down.

–

Use personal protective equipment where needed, such as gloves with good grip and

steel-toed boots where appropriate.

9.3 Safety Practices

– Implement rest breaks and job rotation for frequent and/or heavy lifting.

265

9.2.9 Fire Safety

Fires are classiﬁed based upon the material involved in the ﬁre. It is very important to note that

the ﬁre ﬁghting measures are speciﬁc to the material involved and if these measures are not

followed, it may aggravate the situation or pose additional safety hazards.

CLASS

MATERIAL INVOLVED

MEASURES TO FIGHT SMALL

FIRES

CLASS A

This class of ﬁre involves ordinary Extinguish with pressurized wa-

combustibles or ﬁbrous material,

such as wood, paper, cloth, paper,

and some plastics.

ter, foam, or multipurpose dry

chemical extinguishers. Do not

use carbon dioxide or ordinary dry

chemical extinguishers on Class A

ﬁres.

CLASS B

Class B ﬁre is ﬂammable or com-

bustible liquids such as gasoline,

diesel, kerosene, paint, paint thin-

ners, and propane.

Extinguish Class B ﬁres by remov-

ing oxygen, by preventing vapors

from reaching ignition sources, or

by inhibiting the chemical chain

reaction. Use foam, carbon diox-

ide, ordinary dry chemical, multi-

purpose dry chemical, and halon

extinguishers.

CLASS C

CLASS D

A Class C ﬁre is energized elec-

trical equipment, such as motors,

motor controls, switches panel

boxes, and power tools.

A Class D ﬁre is certain com-

bustible metals, such as magne-

sium, titanium, potassium, and

sodium. These metals bum at high

temperatures and give off sufﬁcient

oxygen to support combustion.

They may react violently with wa-

ter or other chemicals and must be

handled with care.

Extinguish Class C ﬁres by using

carbon dioxide, ordinary dry chem-

ical, multipurpose dry chemical,

and halon-free extinguishers.

Extinguish Class D ﬁres by using

dry powder extinguishers made

especially for this type of ﬁre

Table 9.1: Fires Classiﬁcations

9.3 Safety Practices

9.3.1 Lockout - Tagout (LOTO)

When conducting routine inspections, repairs and maintenance activities, requires meeting the

mandates of Occupational Safety Hazard Administration(OSHAs) Lock-Out/Tag-Out

(LOTO) program

266

Chapter 9. Safety

which is designed to prevent injury or fatalities. It involves preventing an equipment from acci-

dentally starting up and release of all stored energy. Hazardous energy sources include:

• Electrical

• Mechanical

• Hydraulic

• Pneumatic

• Chemical

• Thermal

• Other energy

The LOTO involves established and documented procedures speciﬁc to an equipment or machin-

ery. It typically comprises of:

• Notifying affected employees

• Stopping and isolating the equipment

• Releasing stored energy

• Veriﬁcation of the isolation and de-energization

•

Placing lock-out devices which use a positive means such as a lock, either key or combina-

tion type, to hold an energy isolating device in the safe position and prevent the energizing

of a machine or equipment

•

Appropriately tagging the devices to indicate its non-operation and that it may not be

operated until the tagout device is removed

9.3.2 Personal Protective Equipment (PPE)

Employees depend on personal protective equipment to protect themselves from hazards and

perform daily duties. PPE includes but is not limited to safety glasses, face shields, hard hats,

gloves, foot protection, and durable and disposable chemical-protective clothing. Respirators

and fall protection might also be required. However, respirators and fall protection fall under

separate OSHA standards. The National Institute for Occupational Safety and Health (NIOSH) is

the federal agency responsible for testing and approving respirators used in workplace settings.

9.3.3 Conﬁned Space Entry

OSHA deﬁnes a conﬁned space as an area that:

•

is large enough and so conﬁgured that an employee’s body can enter and perform assigned

work

• has limited or restricted means for entry or exit; and

• is not designed for continuous employee occupancy.

Potentially dangerous conditions which can exist in conﬁned spaces include:

•

Oxygen level: Some gasses are heavier than air and so will ﬁll up a conﬁned space, which

forces oxygen out. The oxygen concentration must not fall below 19.5% at any time. In

plants where pure oxygen is used there is a potential hazard due to high the oxygen con-

centration. Oxygen concentration greater than 23% increases the risk of ignition and ﬁre

9.3 Safety Practices

•

267

Explosive conditions: Many gasses are explosive when present in certain ratios with oxy-

gen. These ratios are deﬁned by the upper explosive limit(UEL) and the lower explosive

limit (LEL). The minimum concentration of a particular combustible gas or vapor neces-

sary to support its combustion in air is deﬁned as the Lower Explosive Limit (LEL) for that

gas. Below this level, the mixture is too “lean” to burn. The maximum concentration of a

gas or vapor that will burn in air is deﬁned as the Upper Explosive Limit (UEL) . Above

this level, the mixture is too “rich” to burn. The range between the LEL and UEL is known

as the ﬂammable range for that gas or vapor.

•

Toxic conditions: This condition could potentially exist due to the presence of gasses such

as carbon dioxide, chlorine and hydrogen sulﬁde.

• Engulfment by liquids

• Electrical hazards

• Mechanical Hazards associated with equipment including mixers

A permit-required conﬁned space is deﬁned as a conﬁned space that:

• contains or has a potential to contain a hazardous atmosphere

• contains a material that potentially could engulf an entrant

•

has an internal conﬁguration that could trap or asphyxiate an entrant through inwardly

converging walls or a ﬂoor that slopes downward and tapers to a smaller cross-section

• contains any serious safety or health hazard

Chapter 9 Assessment

1. What federal law is designed to protect the safety and health of operators?

a. OSHA

b. FMLA

c. FLSA

d. ADEA

2. What are the two most important safety concerns when entering a conﬁned space?

a. Corrosive chemicals and falls

b. Bad odors and claustrophobia

c. Extreme air temperatures and slippery surfaces

d. Oxygen deﬁciency and hazardous gases

3. Which document provides a proﬁle of hazardous substances?

a. CERCLA

b. SARA

c. CFR

d. SDS

4. What is the purpose of a pump guard?

a. Allows operators to turn off pump in emergency situations

b. Notiﬁes operators of excessive temperatures

c. Allows operators to pump against a closed discharge valve

d. Protects operators from rotating parts

5. Atmosphere is considered oxygen deﬁcient when the oxygen level is below

270

Chapter 9. Safety

a. 21.5%

b. 20%

c. 19.5%

d. 17%

6. Employee hazards include

a. Noxious or toxic gases or vapors

b. Oxygen deﬁciency

c. Physical injuries

d. All of the above

7. Before entering a permit-required conﬁned space, you must:

a. Check the atmosphere with a calibrated gas detector.

b. Make notiﬁcation that personnel are entering the space.

c. Lock out and tag out all equipment.

d. All of the above.

8. When making a sulfuric acid dilution, the appropriate method is:

a. Add the water to the acid.

b. Add the acid to the water.

c. Add both at the same time.

d. None of the above.

9. When manually lifting any object, be sure to

a. Hold it at arm’s length.

b. Keep your back bent and hold it low.

c. Keep it close to your body and use leg strength.

d. Keep your knees locked and bend at the waist.

10. What is the proper slope of a ladder?

a. Every 4 feet up the ladder is 1 foot out from the wall.

b. Every 5 feet up the ladder is 1 foot out from the wall.

c. Every 6 feet up the ladder is 1 foot out from the wall.

d. Every 7 feet up the ladder is 1 foot out from the wall.

11. When working on a chemical feed pump, what of the following is not required?

a. Nitrile gloves.

b. Safety glasses.

c. Leather work gloves.

d. Full face shield.

12. When must the atmosphere of a conﬁned space be tested?

a. Only before a worker enters

b. Never, if adequate ventilation exists

c. Continuously

d. Only if welding or painting is being performed

13. Some gases in a conﬁned space can be:

9.3 Safety Practices

271

a. Colorless

b. Odorless

c. Deadly

d. All of the above

14. Why should you contact other area companies with underground utilities before starting an

underground repair job?

a. To determine if there have been recent excavations in that location

b. To ask these companies to mark the location of their utilities in the area of the repair job

c. To see if they also have excavating to do in the area

d. To see if they will help route trafﬁc while you are doing the repair job

15. The only acceptable breathing device to wear while handling chlorine leaks is the

a. Activated carbon canister type

b. Potassium tetroxide canister type

c. Self-contained breathing apparatus

d. Oxygen supply apparatus

Chapter 10

Water Math . . . . . . . . . . . . . . . . . . . . . . . . 269

Fractions

10.1

10.2

10.3

10.4

10.5

10.6

10.7

10.8

10.9

Decimals and Powers of Ten

Rounding and Signiﬁcant Digits

10.10 Concentration

10.11 Density and Speciﬁc Gravity

10.12 Contaminant Removal Efﬁciency

10.13 Pounds Formula

10.14 Blending and Dilution Calculations

10.15 Force, Pressure and Head

10.16 Pumping Calculations

10.17 Well Hydraulics Calculations

10.18 Sedimentation

10.19 Filtration

10. Water Math

Expected Range of Knowledge for Water Math

Water Distribution System Operator License Exams

Ability to calculate ﬂow rates for a storage facility

Ability to calculate the volume of a storage facility

Knowledge of unit conversions

Ability to calculate ﬂow rates

Ability to calculate pipe volumes

Ability to calculate the area of a pipe cross-section

Ability to calculate the surface area of a valve face

Ability to calculate the volume of a cylinder, rectangle, and square

Ability to calculate the volume of a pipe

Ability to calculate the volume of a well, storage reservoir, pipe, trench

Ability to calculate the well draw down

Ability to calculate total force on a valve

Ability to convert pressure to feet of head

Ability to convert units of volume, area, and time

Ability to convert units of volume, area, pressure, and time

Ability to convert units of volume, pressure and area

Ability to convert water units

Ability to calculate a disinfectant dosage

Ability to calculate a dosage

Ability to calculate the volume of a storage reservoir

Ability to calculate the volume of a well

Ability to calculate the volume of a trench

276

Expected Range of Knowledge for Water Math

Chapter 10. Water Math

Water Distribution System Operator License Exams (Continued)

Ability to calculate pipe capacity

Ability to calculate the velocity of water

Ability to calculate thrust block size

Ability to calculate water velocity

Ability to convert a pressure reading to depth of water

Ability to convert a scale to actual distance

Ability to calculate brake-horsepower

Ability to calculate pump efﬁciency

Ability to calculate speciﬁc yield of a well

Ability to calculate the cost of water production

Ability to calculate a water loss rate

Ability to calculate the cost of pumping water

Ability to calculate the hydraulic gradient

Ability to calculate water production costs

Water Treatment Operator License Exams

Ability to calculate ﬂow rates and water velocity

Ability to calculate the volume of water in a storage facility

Ability to calculate well head pressure

Ability to convert common water units (e.g. gallons per minute to MGD)

Ability to convert head pressure to water elevation

Ability to convert units of length, volume, ﬂow and pressure

Ability to determine water level in a storage tank, reservoir, or well

Ability to calculate a chemical dosage

Ability to calculate a chemical solution concentration

Ability to calculate chlorine demand and chlorine residual

Ability to convert common water units, (gallons per minute to MGD, etc...)

Ability to determine water level in a storage tank, reservoir or well

Ability to calculate well drawdown

Ability to calculate detention time

Ability to calculate well speciﬁc capacity

Ability to calculate daily ﬁlter production

Ability to calculate ﬁlter backwash rate

Ability to calculate a CT value

Ability to perform blending calculations

Ability to calculate a dilution factor

Ability to mix chemicals and prepare reagents

Ability to perform dilutions

Ability to calculate a coagulant dose from a jar test

Ability to calculate a ﬁlter-aid dosage

Ability to calculate a ﬁltration rate

Ability to calculate ﬁlter loading rate

Ability to calculate percent or log removal of contaminants from water

Ability to calculate the cost of water treatment operations

10.1 Fractions

277

10.1 Fractions

•

A fraction is deﬁned as part of whole. If in a class there are 20 male students and 30 male

students, the fraction of male students is or .

• It is composed of three items: two numbers and a line.

•

The number on the top is called the numerator, the number on the bottom is called the

denominator, and the line in between them means to divide.

Numerator

Divide −→

Denominator

•

A proper fraction is a fraction that has no whole number part and its numerator is smaller

than its denominator. An improper fraction is a fraction that has a larger numerator than

denominator and it represents a number greater than one.

1 5 11

Proper Fraction Examples:

, ,

2 8 12

12 5

Improper Fraction Examples:

•

Any whole number can be expressed as a fraction by placing a "1" in the denominator. For

example:

2 is the same as and 45 is the same as

Only fractions with the same denominator can be added/subtracted, and only the numera-

tors are added/subtracted. For example:

and,

−

• A fraction combined with a whole number is called a mixed number. For example:

4 , 16 , 8 , 45 and, 12

These numbers are read, four and one eighth, sixteen and two thirds, eight and three

fourths, forty-ﬁve and one half, and twelve and seventeen thirty seconds.

Mized numbers

•

A fraction can be changed by multiplying the numerator and denominator by the same

number. This does not change the value of the fraction, only how it looks. For instance:

is the same as

∗

which is

• Steps to convert

to a mixed number:

Step 1. How many times can 4 ﬁt into 17? 4 because 4×4=16. Thus, 4 becomes the whole

number part

Step 2. How much is left over in the numerator? 1 because 17−16 = 1. Thus, 1 becomes the

278

Chapter 10. Water Math

numerator of the fractional part

Step 3.

•

= 4

To turn a mixed number into an improper fraction, multiply the whole number part by the

denominator and add the numerator. This becomes the new numerator over the original

denominator.

Example: Converting 1.5 feet to fraction

1.5 ft = 1

1∗2+1 2+1

1 =

•

A mixed value - say a circumference is given in feet and fraction of feet (say 7 3/4), needs

to be converted to a fraction for calculation purposes.

10.2 Decimals and Powers of Ten

•

A decimal is composed of two sets of numbers: the numbers to the left of the decimal are

whole numbers, and numbers to the right of the decimal are parts of whole numbers, a

fraction of a number.

•

The term used to express the fraction component is dependent on the number of characters

to the right of the decimal.

– The ﬁrst character after the decimal point is tenths: 0.1 - tenths

– The second character is hundredths: 0.01 - hundredths

– The third character is thousandths: 0.001 - thousandths

Powers of 10 notation enables us to work with these very large and small quantities efﬁ-

ciently.

•

In water math, the most common application of this concept is related to parts per million

(ppm) or parts per billion (ppb).

1 million - 1,000,000 can be represented as 10⁶. Likewise, 1 billion - 1,000, 000,000 can

be represented as 10⁹

• The sequence of powers of ten can also be extended to negative powers.

• 1 part per million (1/1,000,000) can be written as 10⁻6

10.3 Rounding and Signiﬁcant Digits

•

Signiﬁcant digits (also called Signiﬁcant Figures) are digits which give us useful informa-

tion about the accuracy of a measurement and are related to rounding.

•

This concept is used to determine the direction to round a number (answer). The basic

idea is that no answer can be more accurate than the least accurate piece of data used to

calculate the answer.

•

Signiﬁcant digits is the count of the numerals in a measured quantity (counting from the

left) whose values are considered as known exactly, plus one more whose value could be

10.3 Rounding and Signiﬁcant Digits

279

Name

one

ten

hundred

thousand

million

billion

tenth

Power

10⁰

Number

SI symbol SI preﬁx

10¹

da (D)

h (H)

k (K)

deca

hecto

kilo

mega

giga

10²

100

1,000

1,000,000

1,000,000,000

0.1

0.01

0.001

0.000 001

0.000 000 001

10³

10⁶

10⁹₋₁

10₋₂

deci

hundredth 10

centi

milli

micro

nano

thousandth 10⁻³

millionth

billionth

10⁻⁶

10⁻⁹

one more or one less.

• Rules for determining the number of signiﬁcant digits:

1. All nonzero digits are signiﬁcant:

1.234 g has 4 signiﬁcant ﬁgures, and 1.2 g has 2 signiﬁcant ﬁgures.

2. Zeroes between nonzero digits are signiﬁcant: 1002 kg has 4 signiﬁcant ﬁgures, 3.07

mL has 3 signiﬁcant ﬁgures.

3. Zeroes to the left of the ﬁrst nonzero digits are not signiﬁcant; such zeroes merely

indicate the position of the decimal point: 0.001 ^◦C has only 1 signiﬁcant ﬁgure,

0.012 g has 2 signiﬁcant ﬁgures.

4. Zeroes to the right of a decimal point in a number are signiﬁcant: 0.023 mL has 2

signiﬁcant ﬁgures, 0.200 g has 3 signiﬁcant ﬁgures.

5. When a number ends in zeroes that are not to the right of a decimal point, the zeroes

are not necessarily signiﬁcant: 190 miles may be 2 or 3 signiﬁcant ﬁgures, 50,600

calories may be 3, 4, or 5 signiﬁcant ﬁgures. The potential ambiguity in the last

rule can be avoided by the use of standard exponential, or ”scientiﬁc,” notation. For

example, depending on whether 3, 4, or 5 signiﬁcant ﬁgures is correct, we could

write 50,600 calories as: 5.06∗10⁴calories (3 signiﬁcant ﬁgures) 5.060∗10⁴calories

(4 signiﬁcant ﬁgures), or 5.0600∗10⁴) calories (5 signiﬁcant ﬁgures).

• Examples of signiﬁcant ﬁgures:

• Addition and Subtraction

–

When you are adding or subtracting a bunch of numbers and need to be concerned

with signiﬁcant ﬁgures, ﬁrst add (or subtract) the numbers given in their entire for-

mat, and then round the ﬁnal answer. When rounding the ﬁnal answer after adding or

subtracting, the answer must be written with the same signiﬁcant ﬁgures as the least

accurate decimal place given.

Example: 13.214 + 234.6 + 7.0350 + 6.38

13.214 + 234.6 + 7.0350 + 6.38 = 261.2290

234.6 is only accurate to the tenths place making it the least accurate number.

280

Chapter 10. Water Math

1000 has one signiﬁcant digit: only the 1 is interesting (only it tells us anything speciﬁc); we don’t know anything for sure about the hundreds,

tens, or units places; the zeroes may just be placeholders; they may have rounded something off to get this value.

1000.0 has ﬁve signiﬁcant digits: the ".0" tells us something interesting about the presumed accuracy of the measurement being made;

namely, that the measurement is accurate to the tenths place, but that there happen to be zero tenths.

0.00035 has two signiﬁcant digits: only the 3 and 5 tell us something; the other zeroes are placeholders, only providing information about

relative size.

0.000350 has three signiﬁcant digits: the last zero tells us that the measurement was made accurate to that last digit, which just happened to

have a value of zero.

1006 has four signiﬁcant digits: the 1 and 6 are interesting, and we have to count the zeroes, because they’re between the two interesting

numbers.

560 has two signiﬁcant digits: the last zero is just a placeholder.

560. : notice that "point" after the zero! This has three signiﬁcant digits, because the decimal point tells us that the measurement was made to

the nearest unit, so the zero is not just a placeholder.

560.0 has four signiﬁcant digits: the zero in the tenths place means that the measurement was made accurate to the tenths place, and that there

just happen to be zero tenths; the 5 and 6 give useful information, and the other zero is between signiﬁcant digits, and must therefore also be

counted.

My answer must be rounded to the same place as the least accurate number:

261.2290 rounds to 261.2 (one decimal place)

• Multiplication and Division

–

When multiplying or dividing multiple numbers you would do these calculations as

normal. When the answer must be written in the appropriate signiﬁcant ﬁgure your

answer must round to the same number of signiﬁcant ﬁgures as the least number of

signiﬁcant ﬁgures.

Example 1: Simplify, and round, to the appropriate number of signiﬁcant digits

16.235 x 0.217 x 5

Step 1. First off, 5 has only one signiﬁcant ﬁgure, thus the ﬁnal answer needs to be

rounded to one signiﬁcant digit

Step 2. 16.235 x 0.217 x 5 = 17.614975

Step 3. To round 17.614975 to one digit. I’ll start with the 1 in the tens place. Immedi-

ately to its right is a 7, which is greater than 5, so 1 is rounded up to 2, and then

replacing the 7 with a zero, and dropping the decimal point and everything after

it.

Step 4. 17.614975 rounds to 20

Example 2: Simplify, and round, to the appropriate number of signiﬁcant ﬁgures

0.00435 x 4.6

Step 1. 4.6 has only 2 signiﬁcant ﬁgures, so the ﬁnal answer should be rounded to two

signiﬁcant ﬁgures.

Step 2. 0.00435 x 4.6 = 0.02001

Step 3. 0.02001 would round to 0.020, which has 2 signiﬁcant ﬁgures (0.020). The an-

swer cannot be 0.02, because that value would have only one signiﬁcant ﬁgure.

A number is rounded off by dropping one or more numbers from the right and adding

zeroes, if necessary, to maintain the decimal point.

•

10.4 Working with Percent

281

•

If the last ﬁgure dropped is 5 or more, increase the last retained ﬁgure by 1. If the last digit

dropped is less than 5, do not increase the last retained ﬁgure.

10.4 Working with Percent

• Percent expresses portions of the whole.

•

The whole is considered as 1 or 100% and a part of the whole can be expressed as a per-

cent. Example: If a tank is 1/2 full, we say that it contains 50% of the original solution.

• Percentage is written as a whole number with a % sign after it.

• In a calculation, percent is expressed as a decimal.

• The decimal form of a percent value is obtained by dividing the percent by 100.

Example: 11% is expressed as the decimal 0.11, since 11% is equal to 11/100. This deci-

mal is obtained by dividing 11 by 100.

• To determine what percentage a part is of the whole, divide the part by the whole.

Example: There are 80 water meters to read, Jim has ﬁnished 24 of them. What percent-

age of the meters have been read?

24÷80 = 0.30

The 0.30 is converted to percent by multiplying the answer by 100.

0.30∗100 = 30%

Thus 30% of the 80 meters have been read.

•

To ﬁnd the percentage of a number, multiply the number by the decimal equivalent of the

percentage given in the problem.

Example:

What is 28% of 286?

Step 1. Change the 28% to a decimal equivalent:

28%÷100 = 0.28

Step 2. Multiply 286∗0.28 = 80

Thus 28% of 286 is 80.

•

To increase a value by a percent, add the decimal equivalent of the percent to " 1 " and

multiply it times the number.

Example: A ﬁlter bed will expand 25% during backwash. If the ﬁlter bed is 36 inches

deep, how deep will it be during backwash?

Step 1. Change the percent to a decimal.

25%÷100 = 0.25

282

Step 2. Add the whole number 1 to this value.

1+0.25 = 1.25

Chapter 10. Water Math

Step 3. Multiply times the value.

36 in ∗1.25 = 45 inches

10.5 Averages

•

Also known as arithmetic mean, this value is arrived at by adding the quantities in a series

and dividing the total by the number in the series.

Example Problems:

1. Find the average of the following series of numbers: 12,8,6,21,4,5 , 9 , and 12.

Adding the numbers together we get 77.

There are 8 numbers in this set.

Divide 77 by 8.

= 9.6 is the average of the set

2. Find the average of the set of daily turbidity data - 0.3,0.4,0.3,0.1,and 0.8

The total is 1.9.

There are 5 numbers in the set.

Therefore:

1.9

= 0.38, rounding off = 0.4

10.6 Ratio and Proportion

Ratio:

• Ratio is used for comparing the size of two or more quantities.

•

Say if there are 10 red cubes and 5 pink marbles in a bag, the ratio

marbles and red cubes. It can also be represented by 5:10.

is the ratio of pink

• 5 lbs of chemical in 10 gallons solution is a ratio. So is 30 miles per gallon.

• Unlike fractions, ratio does not compare things that have the same units.

Proportion:

Two quantities are said to be in proportion if one changes, the other changes in a speciﬁc

•

way.

•

Two quantities are said to be directly proportional, if the increase in one will increase the

other value proportionally.

–

Thus, if two quantities x and y are directly proportional, its ratio will be a ﬁxed

value. Thus for x₁and y₁different values of x and y respectively will be related by

x₁

y₁

the equation

This relationship is useful for calculating unknown values in water treatment calcula-

tions as in the following example:

10.6 Ratio and Proportion

283

Knowing 200 lbs of bleach is needed to disinfect 5 MG of water at a treatment plant,

calculate the lbs of bleach required to disinfect 3.2 MGD ﬂow.

200 pounds bleach

The ratio

or 40 lbs bleach per MG is a constant. Using this

5MG

known proportion the lbs of bleach is needed to disinfect 3.2 MG at this plant can be

calculated as follows by setting up the equation as:

40 pounds bleach

where X is the unknown lbs of bleach that is required

3.2 MG

to disinfect the 3.2 MG ﬂow.

3.2∗40

X can be calculated by cross multiplying the above equation: X =

= 128 lbs bleach

•

Two quantities are said to be inversely proportional if the increase in one will decrease the

other value proportionally.

–

Thus, if two quantities x and y are inversely proportional, its product x ∗ y will be a

ﬁxed value and different values of x and y respectively will be related by the equation

x∗y = x₁∗y₁.

– Examples of inversely proportional relationship include:

Labor hours required to perform a certain task or time required to pump down a

wetwell depending on the size of the pump. An increase in assignment of labor

hours will reduce the time required to perform the task

Using a larger pump will reduce the time to pump down the wetwell.

In the Pounds formula:

ꢂ

ꢃ

lbs

lbs or

= Concentration

∗8.34∗volume(MG) or Flow(MGD)

day

for the same lbs or lbs/day, concentration varies inversely with volume or ﬂow.

Thus, for a certain pounds added, the concentration will go down if the ﬂow

increases and vice versa.

In the ﬂow equation, Q=V*A, for the same ﬂow (Q), velocity (V) and surface

area (A) are inversely related. If Q is remaining the same, an increase in surface

area will reduce the velocity and vice versa.

Additionally, for a ﬂow through a pipe as the surface area of the pipe is propor-

tional to the square of the diameter, the velocity in the pipe is inversely propor-

tional to the square of the diameter.

For a constant Q: V ∗A = V₁∗A₁or V ∗D²= V₁∗D₁²

–

Application of inversely proportional relationship in water related calculation can be

demonstration with the following example:

If it takes 20 minutes to pump a wet well down with one pump pumping at 125 gpm,

then how long will it take if a 200 gpm pump is used?

As this is an inversely proportional relationship ( a larger pump will reduce the time

required):

284

Chapter 10. Water Math

(20minutes∗125gpm) = (Xminutes∗200gpm)

where X is the unknown time to pump down the wetwell with the 200 gpm pump.

20∗125

Solving for X: X =

= 12.5 minutes

200

10.7 Area and Volume

Example Problems:

1. The ﬂoor of a rectangular building is 20 feet long by 12 feet wide and the inside walls are

10 feet high. Find the total surface area of the inside walls of this building

Solution:

Ceiling=W*L

Wall - L*H

Wall - W*H

Height=10’

Wall - W*H

Wall - L*H

Floor=W*L

Length=20’

Width=12’

2 Walls W*H + 2 Walls L*H= 2∗12∗10 ft²+2∗20∗10 ft²

= 240+400 = 640ft²

2 Walls W*H + 2 Walls L*H + Floor + Ceiling= 2 ∗ 12 ∗ 10ft²+ 2 ∗ 20 ∗ 10 ft²+ 2 ∗ 12 ∗

20 ft²

= 240+400+480 = 1,120ft²

2. How many gallons of paint will be required to paint the inside walls of a 40 ft long x 65 ft

wide x 20 ft high tank if the paint coverage is 150 sq. ft per gallon. Note: We are painting

walls only. Disregard the ﬂoor and roof areas.

10.8 Flow and Velocity

285

Solution:

Wall - L*H

Wall - W*H

Wall - L*H

Height=20’

Length=40’

Width=65’

2 Walls W*H + 2 Walls L*H = 2∗65∗20 ft²+2∗40∗20ft²= 2,600+1,600 = 4,200ft²

ft²

gal

4,200ft²

=⇒ @150

paint coverage →

= 28 gallons

ft²

150

gal

3. What is the circumference of a 100 ft diameter circular sedimentation tank?

Solution:

Circumference = π ∗D = 3.14∗100ft = 314ft

4. If the surface area of a clariﬁer is 5,025ft², what is its diameter?

Solution:

Sur face area = ∗D²=⇒ 5025(ft²) = 0.785∗D²(ft²)

√

5025

0.785

=⇒ D²=

=⇒ D = 6401.3 = 80 ft

5. How many gallons of water would 600 feet of 6-inch diameter pipe hold, approximately?

Solution:

Diameter=6"

Length=600’

Volume =

ꢂ

ꢃ

gallons

ft³

D²∗L = 0.785∗

∗600ft³∗7.48

= 881 gallons

10.8 Flow and Velocity

• Flow Rate - Q (volume/time) = velocity (distance or length traveled /time) * surface area

•

Velocity is the speed at which the water is ﬂowing. It is measured in units of length/time –

ft./sec.

•

Velocity of water ﬂowing through can be calculated by dividing the ﬂow rate by area of the

ﬂow stream.

volume or cubic length

time

sur face area in the direction of flow−square length

flow rate(

)

length

time

Velocity

286

Chapter 10. Water Math

For a ﬂow in a channel:

For a ﬂow in a pipe:

Example Problems:

1. If a chemical is added in a pipe where water is ﬂowing at a velocity of 3.1 feet per second,

how many minutes would it take for the chemical to reach a point 7 miles away?

Note - we want the answer in minutes

1 sec 5280 ft

min

60sec

Min =

∗

∗7miles∗

= 199min

3.1 ft

mile

2. Find the ﬂow in cfs in a 6-inch line, if the velocity is 2 feet per second.

sec

ft²

2∗0.785∗36

ꢀ

ꢁ

Q=Velocity * Area= =⇒ Q

= 2

∗

∗ (6 in)²∗

144 in²

144

ft³

0.4

sec

3. A rectangular channel 3 ft. wide contains water 2 ft. deep ﬂowing at a velocity of 1.5 fps.

What is the ﬂow rate in cfs?

sec

ft³

sec

Q = V ∗A =⇒ Q = 1.5

∗(3∗2)ft²= 9

10.9 Unit Conversions

•

A conversion is a number that is used to multiply or divide into a measure in order to

change the units of the original measure.

•

In most instances, the conversion factor cannot be derived. It must be known. Therefore,

tables such as the one below are used to ﬁnd the common conversions.

10.9 Unit Conversions

287

Measure

Length

Area

Volume

Density

Flow

Units

inches, ft, miles

ft², acres

ft³, gallons, acres-ft.

weight per volume, lbs/ft³, lbs/gallon

ft³/min, MGD, acres-ft/day

Table 10.1: Common units in water calculations

Some Common Conversions

Weight

Linear Measurements

1 inch = 2.54 cm

1foot = 30.5 cm

1ft³of water = 62.4lbs

1gal = 8.34lbs

1lb = 453.6grams

1 meter = 100 cm = 3.281feet = 39.4 inches 1 1 kg = 1000 g = 2.2lbs

acre = 43,560ft²

1% = 10,000mg/l

1pound = 16ozdrywt

1ft³= 62.4lbs

1yard = 3feet

Volume

Pressure

1gal = 3.78 liters

1ft = 7.48 gal

1 L = 1000 mL

1gal = 16cups

Flow

1ft of head = 0.433psi

1psi = 2.31ft of head

1cfs = 448gpm

1gpm = 1440gpd

• Common conversions in water related calculations include the following:

– gpm to cfs

– Million gallons to acre feet

– Cubic feet to acre feet

– Cubic feet of water to gallons

– gpm to MGD

– psi to feet of head

• Steps for unit conversion:

Step 1: Make sure the original unit is for the same measurement as the converted (desired)

unit. So if the original unit is for area, say in ft²the converted unit should be another

area unit such as in²or acre but it cannot be gallons as gallon is a unit of volume.

Note: Calculating the weight of a certain volume of water involves the use of density

which is the mass per volume - value in units including lbs/gallon or lbs/ft³

Step 2: Write down the conversion formula as:

Conversion unit

(

Quantity in converted unit = Quantity (Original Unit)∗Conversion Factor

(

Original unit

(

288

Chapter 10. Water Math

•

Note: If you wish to convert cubic feet of water to pounds, you have to use its density

which is the known mass per unit volume.

8.34 lbs

62.4 lbs

gallon

ft³

mass

ꢀ

mass of water = Volume∗Density(

)

ꢀ

Volume

ꢀ

Example Problems:

1. Convert 1000 ft³to cu. yards

cu.yards

1000 ft³∗

= 37cu.yards

27 ft³

2. Convert 10 gallons/min to ft³/hr

Note: This involves use of two conversion factors - one for converting gallons to cubic feet

and another for converting minute to gallons.

ꢀ

10gallons

ft³

60min 80.2 ft³

ꢀ

∗

ꢀ

min

7.48gallons

ꢀ

3. Convert 100,000 ft³to acre-ft.

acre− ft

100,000ft³∗

= 2.3acre− ft

ꢀ

43,560ft − ft

ꢀ

4. Convert 8 ft³of water to pounds.

Here the conversion is from a volume (ft³) to a weight (lbs). It involves use of a standard

correlation of the volume of water to its weight - its density.

lbs

ft³

Weight of water in lbs = 8 ft³∗62.4(

) = 499.2 lbs

10.9.1 Temperature Conversion

•

Two scales are commonly used to measure temperature: degrees Fahrenheit (^◦F) and de-

grees Centigrade or Celsius(^◦C).

• Fahrenheit is the standard scale used in the U.S. and Celsius is the metric scale.

•

In the Celsius scale, water freezes at 0^◦C and boils at 100^◦C. In the Fahrenheit scale, water

freezes at32^◦F and boils at 212^◦F.

• The following factors can be used when converting from one temperature scale to another:

^◦F −32

^◦C =

1.8

^◦F = (^◦C ∗1.8)+32

10.10 Concentration

Concentration is typically expressed as mg/l which is the weight of the constituent (mg) in

•

1 liter of water.

•

As 1 liter of water weighs 1 million mg, a concentration of 1 mg/l implies 1 mg of con-

stituent per 1 million mg of water or one part per million (ppm). Thus, mg/l and ppm are

synonymous.

• Sometimes the constituent concentration is expressed in terms of percentage.

10.10 Concentration

Example: 12.5% chlorine concentration solution.

289

100% would mean 1,000,000 mg/l or 1,000,000 ppm

1,000,000

=⇒ 1% would be

mg/l = 10,000 mg/l or 10,000 ppm

100

=⇒ 12.5% chlorine concentration is 125,000 mg/l or 125,000 ppm.

1% concentration = 10,000 ppm or

0.1% concentration = 1,000 ppm or

0.01% concentration = 100 ppm or

10% concentration = 100,000 ppm or

5% concentration = 50,000 ppm or

12.5% concentration = 125,000 ppm or

Above concepts are used for chemicals such as ﬂuoride and hypochlorites - the strength of the

product as used is commonly expressed as a percentage.

Example Problem:

1. A chlorine solution was made to have a 4% concentration. It is often desirable to deter-

mine this concentration in mg/l. This is relatively simple: the 4% is four percent of a

million.

To ﬁnd the concentration in mg/l when it is expressed in percent, do the following:

1. Change the percent to a decimal.

4%÷100 = 0.04

2. Multiply times a million.

0.04∗1,000,000 = 40,000mg/l

We get the million because a liter of water weighs 1,000,000mg.1mg in 1 liter is 1 part in

a million parts ( ppm).1% = 10,000mg/l.

2. How much 65% calcium hypochlorite is required to obtain 7 pounds of pure chlorine?

65% implies that in every lb of calcium hypochlorite has 65% lbs of available chlorine.

0.65 lbs available chlorine

lb of calcium hypochlorite

0.65 lbs available chlorine

Therefore,

or conversely

(

lb of calcium hypochlorite 7 lb of a(vailable chlorine

(

=⇒ lbs calcium hypchlorite required =

∗

(

0.65 lbs available chlorine

(

= 10.8 lbs of calcium hypochlorite with 65%available chlorine is required

290

Chapter 10. Water Math

10.11 Density and Speciﬁc Gravity

10.11.1 Density

•

Density is deﬁned as the weight of a substance per a unit of its volume. For example,

pounds per cubic foot or pounds per gallon.

• Here are a few key facts about density:

–

Density is measured in units of lb/ft3, lb/gal, or mg/L. Density of water = 62.4 lb/ft3

= 8.34 lb/gal.

10.11.2 Speciﬁc Gravity

•

Speciﬁc gravity is the ratio of the density of a substance (liquid or solid) to the density

water.

It is the ratio of the weight of the substance of a certain volume to the weight of water of

the same volume.

Any substance with a density greater than that of water will have a speciﬁc gravity greater

than 1.0. Any substance with a density less than that of water will have a speciﬁc gravity

less than 1.0.

• Speciﬁc gravity examples:

– Speciﬁc gravity of water = 1.0

– Speciﬁc gravity of concrete = 2.5 (depending on ingredients)

– Speciﬁc gravity of alum (liquid @ 60°F) = 1.33

– Speciﬁc gravity of hydrogen peroxide (35%) = 1.132

• Speciﬁc gravity is used in two ways:

1. To calculate the total weight of a % solution (either as a single gallon or a drum

volume).

Total Weight = Drum Vol X SG X 8.34

2. To calculate the “active ingredient” weight of a single gallon or a drum.

Active Ingredient Weight within Drum = Drum Volume X SG X 8.34 X % solution as

a decimal. (i.e., Total Weight X % solution as a decimal)

NOTE: Both ways start with solving for the total weight (Drum Vol X SG X 8.34).

When solving for “active ingredient” weight, you have to then multiply by % solution

as a decimal.

Example Problem:

1. What is the weight of 5 gallons of a 40% ferric chloride solution given its speciﬁc gravity

of 1.43?

(8.34∗1.43) lbs/gal ∗5 gallons = 59.6 lbs

The weight of active ferric chloride in the drum will be 59.6*0.4=23.84 lbs (as ferric chlo-

ride is 40% strength)

10.12 Contaminant Removal Efﬁciency

291

10.12 Contaminant Removal Efﬁciency

•

The removal efﬁciency of a certain constituent in a treatment process is frequently reported

as the percent (%) removal efﬁciency If C_Inis the concentration of the constituent entering

the process and C_Outis the concentration of that constituent leaving the process

C_In

C_Out

Process

Removal E f ficiency = RE%

C_In−C_Out

• Removal E f ficiency (%) =

∗100

C_In

•

If 10 units of a contaminant are entering a process and 8 units of pollutant are leaving (pro-

cess removes 2 units), then the process removal rate for that pollutant is (10-8)/10*100=20%.

In this example the process is 20% efﬁcient in removing that particular contaminant.

For water pathogens including coliforms, viruses and parasites (Giardia and Crypto), their

removal is expressed in terms of log reduction. This is because the pathogens entering and

exiting the process are quantiﬁed as numbers and as these numbers can be very large, their

concentrations are expressed in terms of their order of magnitude using their log₁₀value

instead of their absolute values.

•

log₁₀C_In

log₁₀C_Out

Process

Removal E f ficiency = log Reduction

Log Reduction = log₁₀C_In- log₁₀C_Out. Thus:

1 log removal =90% removal efﬁciency

2 log removal =99% removal efﬁciency

3 log removal =99.9% removal efﬁciency

4 log removal =99.99% removal efﬁcnecy

292

Chapter 10. Water Math

Example Problems:

1. Calculate the removal efﬁciency if the C_Invalue of E. Coli is 1.00*10⁸MPN/100ml and

C_Outis 1.00*10⁵MPN/100ml.

1.00*10⁸MPN/100ml

1.00*10⁵MPN/100ml

Process

Removal E f ficiency(RE%)orlog Reduction

Using the Removal Efﬁciency % Method:

C_In−C_Out

1.00∗10⁸−1.00∗10⁵

1.00∗10⁸

Removal E f ficiency (%) =

∗100 =

∗100 = 99.9%

C_In

Using the log Reduction Method:

Log Reduction = log₁₀C_In- log₁₀C_Out= log₁₀1.00*10⁸-log₁₀1.00*10⁸=8-5=3

2. What is the % removal efﬁciency if the inﬂuent concentration is 10 mg/L and the efﬂuent

concentration is 2.5 mg/L?

In−Out

10−2.5

Removal Rate(%) =

∗100 =⇒

∗100 = 75%

10.13 Pounds Formula

• Pounds formula:

ꢂ

ꢃ

lbs

day

lbs or

= Concentration

∗8.34∗volume(MG) or Flow(MGD)

•

So if the concentration of a particular constituent (in mg/liter) and the volume or ﬂow of

water is given, one can calculate the amount of that constituent or using this formula.

Important notes:

1. The unit of the constituent loading rate will be in lbs per the unit of time the ﬂow is

expressed in. So if the ﬂow is in MG per day the calculated loading rate will be in

lbs/day. Likewise if the ﬂow value used is in MG per minute, the calculated loading

rate will be in lbs/min.

2. If volume is used, the calculated value will be the mass of the constituent in that

volume. If ﬂow is used, the calculated value will be the mass of the constituent in

that ﬂow.

3. For the Pound Formula to work, the volume or ﬂow needs to be expressed in MG.

Volume or ﬂows in other units - gallons, ft³etc. needs to be converted to MG.

The formula assumes that all of the material found in water (TSS, BOD, MLSS, Chlorine,

etc.) weighs the same as water, that is, 8.34 pounds per gallon.

•

10.13 Pounds Formula

293

• In the Pounds Formula, there are three variables – lbs, concentration and volume, and one

constant - 8.34. Knowing any of the two variables in the formula, one can calculate the

third (unknown) variable by rearranging the equation.

lbs or lbs/day

Concentration

mg/l

Volume(MG)

Flow(MGD)

8.34

Multiply

Figure 10.1: Davidson Pie

•

Davidson Pie provides a pictorial reference for calculating any unknown variable. If for

example, if Concentration is unknown, it can be calculated as follows:

lbs

lbs or

ꢂ

ꢃ

day

Concentration

8.34∗Volume(MG) or Flow(MGD)

• Likewise, if Volume (or Flow) is the unknown variable. it can be calculated as:

lbs

lbs or

day

ꢂ

ꢃ

Volume(MG) or Flow(MGD) =

Concentration

∗ 8.34

• Pounds formula is used for:

–

Calculating the quantity in pounds of a particular water constituent entering or leav-

ing a treatment process

– Calculating the pounds of chemicals to be added

10.13.1 Chemical Dosing

• Use lbs formula to calculate the lbs of chemicals required

•

Using the calculated lbs chemical required value, calculate the amount of that chemical at

the concentration available

Example Problems:

1. If a 5 MGD ﬂow is to be dosed with 25 mg/l of a certain chemical, calculate the lbs/day

that chemical required.

294

Chapter 10. Water Math

Solution

Applying lbs formula:

lbs

day

lbs

= 5MGD∗250

∗8.34 = 1,042

day

2. Calculate the lbs of chemical in 7,500 gallons of 4.5% active solution of that chemical.

Solution

Applying lbs formula:

7500

lbs chemical =

MG∗4.5∗10,000∗8.34 = 2,815 lbs

1,000,000

3. Determine the chlorinator setting (lb/day) required to treat a ﬂow of 4MGD with a chlorine

dose of 5mg/l.

Chlorine feed rate (lb/ day ) = Chlorine (mg/l)∗ Flow (MGD)∗8.34lb/gal

Chlorine feed rate lb/day =5mg/l∗4MGD∗8.34lb/gal = 167lb/day

4. A pipeline that is 12 inches in diameter and 1400ft long is to be treated with a chlorine

dose of 48mg/l. How many lb of chlorine will this require?

Solution:

First determine the volume of the pipeline in MG:

7.48gal

Pipe Volume (MG) = 0.785∗D²(ft²)∗length(ft)∗

∗

1,000,000gal

ft³

7.48gal

1,000,000gal

= 0.785∗(1ft)²∗1400ft∗

∗

= 0.008221MG

ft³

Next calculate the amount of chlorine required using pounds formula:

Chlorine required (lbs)=Chlorine mg/l * Pipe Volume (MG) * 8.34

=⇒ 48mg/l∗0.008221MGD∗8.34lb/gal = 3.3lbschlorine

5. A water sample is tested and found to have a chlorine demand of 1.7mg/l. If the desired

chlorine residual is 0.9 mg/l, what is the desired chlorine dose (in mg/l)?

Chlorine Dose (mg/l) = Chlorine Demand

2.6mg/l

+ Chlorine Residual= 1.7mg/l + 0.9mg/l =

6. The chlorine dosage for water is 2.7mg/l. If the chlorine residual after a 30-minute contact

time is found to be 0.7mg/l, what is the chlorine demand (in mg/l )?

Chlorine Demand = Chlorine Dose − Chlorine Residual

Chlorine Demand = 2.7mg/l−0.7mg/l = 2.0mg/l

7. How many gallons per day of bleach solution (SG 1.2)containing 12.5% available chlorine

is required to disinfect a 10 MGD ﬂow of water given the required chlorine dosage of 7

mg/l.

(a) Calculate the lbs of chlorine required using the lbs formula:

=10MGD ∗ 7

∗ 8.34 = 583.8 lbs chlorine per day

10.14 Blending and Dilution Calculations

295

(b) Calculate the gallons of bleach which will provide the 583.8 lbs chlorine

Applying the lbs formula - note that 8.34 * SG will give the actual lbs/gal of bleach.

If SG is not provided, use only 8.34 lbs per gallon:

lbs bleach

day

gal

day

lbs bleach lbs chlorine

∗ 0.0125

gal lb bleach

583.8

= x

∗ 8.34∗1.2

gal

day

583.8

8.34∗1.2∗0.125

gal

day

=⇒ x

= 467

The above problem can be solved directly using the formula below given in the SWRCB

Water Treatment Exam Formula Sheet.

(MGD)∗(ppm or mg/l)∗8.34 lbs/gal

% purity∗Chemical Wt. (lbs/gal)

10∗7∗8.34

gal

day

GPD =

= 467

0.125∗(1.2∗8.34)

10.14 Blending and Dilution Calculations

• Blending and dilution calculations apply to the following scenarios:

–

Blending involves mixing two streams - each with a different concentration of con-

taminant/chemical, to obtain a certain volume or ﬂow containing the target concentra-

tion of contaminant/chemical. For example: Finding the correct blend of two source

water streams - one with 15 mg/L of iron and other containing 4 mg/L of iron to get a

100 gpm product water containing 8 mg/l of iron. OR

Calculating the actual combined TDS concentration obtained by mixing two known

ﬂows with known TDS concentrations.

–

Dilution involves makedown of a higher concentration of a chemical to a lower con-

centration using water as a dilutant. For example: How much initial volume of a 4%

polymer solution is needed to make 3500 gallons of polymer at 0.25% concentra-

tion?

• These type of problems are solved using C*V relationship where:

– C is the concentration expressed in ppm or mg/l or as % purity.

– V is either the volume or ﬂow.

mass

volume/ﬂow

– The product - C*V -

∗volume/ﬂow = mass

•

For blended streams, the sum of the mass from each of the two source streams will equal

to the mass in the target stream:

• Thus, for blending calculations, if:

C₁and V₁is the concentration and volume respectively of the one of the sources streams

and

C₂and V₂is the concentration and volume respectively of the second source stream, and

C₃and and V₃is the concentration and volume respectively of the target stream

296

Chapter 10. Water Math

The sum of the mass from each of the two source streams will equal to the mass in the

target stream:

C₁* V₁+ C₂* V₂= C₃* V₃.

This equation can be manipulated algebraically to calculate anyone of the unknown values

in the equation.

Also, any of the three volume variables can be expressed as the sum or difference of the

other two - , or V₁+ V₂= V₃or V₁= V₃- V₂or V₂= V_T- V₁

•

For dilution, the mass of the target chemical will remain the same, as only water is added

to the source (concentrated chemical).

• Thus, for dilution calculations, if:

C₁and V₁is the concentration and volume respectively of the concentrated product used

for the dilution, and

C₂and V₂is the concentration and volume of the resultant product after dilution with

water

The mass of the target chemical in the volume of the concentrated product used for dilu-

tion will remain the same in the ﬁnal diluted product:

C₁* V₁= C₂* V₂.

Example Problems:

1. Two wells are used to satisfy demand during the summer months. One well produces water

that contains 22 mg/L of Arsenic. The other well produces water that contains 3 mg/L of

Arsenic. If the total demand for water is 400 gpm and the target Arsenic concentration in

the ﬁnished water is 8 mg/L, what is the highest pumping rate possible for the ﬁrst well?

Solution:

C₁* V₁+ C₂* V₂= C₃* V₃

Thus 22 * V₂₂+ 3 * V₃= 8 * V₈

V₂₂+ V₃= V₈= 400 gpm

As we want to solve for V₂₂, we can express V₃as: V₃= 400-V₂₂

Thus, 22 * V₂₂+ 3 * (400-V₂₂) = 8 * 400=3,200

22V₂₂+ 1200-3V₂₂= 3,200

V₂₂(22-3) = 2,000

2,000

V₂₂

= 105.3 gpm

Also, V₃=400-105.3=294.7

10.15 Force, Pressure and Head

297

NOTE: If one does not want to utilize algebraic manipulation, one may memorize the

following formula:

|C₃−C_2/1|∗V₃

V_1/2

C₁−C₂

Applying the formula above to Example Problem

|8−3|∗400

V₂₂=

V₃=

= 105.3 gpm

= 294.7 gpm

22−3

|8−22|∗400

22−3

2. How many gallons of a 4% polymer solution is required to make a 3,500 gallon batch of

0.25% polymer solution.

Here, we are adding water - which has zero percent of polymer concentration to the 4%

polymer to make a 0.25% polymer solution.

C₁* V₁= C₂* V₂

C_4%* V_4%= C_0.25%* V_0.25%

4 * V_4%= 0.25 * 3,500

0.25 ∗ 3500

= 219 gal

=⇒ V_4%

Take 219 gallons of the 4% polymer and dilute to 3,500 gallons to give a 0.25% polymer

solution.

10.15 Force, Pressure and Head

Force: In the English system force and weight are often used in the same way. The weight of

the cubic foot of water is 62.4 pounds. The force exerted on the bottom of the one foot cube is

62.4 pounds. If we have two cubes stacked on top of one another, the force on the bottom will be

124.8 pounds.

Pressure: Pressure is a force per unit of area, pounds per square inch or pounds per square foot

are common expressions of pressure.

Head: Pressure is directly related to the height of a column of ﬂuid. This height is called head or

feet of head. Pressure and feet of head head are directly related - for every one foot of head there

is a pressure of 0.433 psi.

0.433 psi

ft (water column)

1 ft (water column)

2.31 psi

Thus,

or conversely

Note: This pressure/head will include the height the water pumped and also the head associated

with friction losses - energy loss because of the water moving through the pipe and ﬁttings.

The pressure at the bottom of a container is affected only by the height of water in the container

and not by the shape or the volume of the container. In the drawing below there are four contain-

298

Chapter 10. Water Math

Force

Area

Pressure =

12"

Pressure exerted by

a 1ft column of water

62.4 lb

12in x 12in

= 0.43 psi

12"

As 1ft³of water weighs 62.4 lbs

12"

ers all of different shapes and sizes. The pressure at the bottom of each is the same.

The pressure exerted at the bottom of a tank is relative only to the head on the tank and not the

volume of water in the tank. For example, below are two tanks each containing 5000 gallons.

The pressure at the bottom of each is 22 psi. If half of the water were drained from the tanks the

pressure at the bottom of the elevated tank would be 17.3 psi while the pressure at the bottom of

the standpipe would be 11 psi.

Example Problems:

1. A reservoir is 40 feet tall. Find the pressure at the bottom of the reservoir.

40ft∗0.433psi/ft = 17.3psi

10.16 Pumping Calculations

299

2. Find the height of water in a tank if the pressure at the bottom of the tank is 12 psi.

12psi÷0.433psi/ft = 27.7ft

3. If a pump discharge pressure gauge read 10 psi, the height of the water corresponding to

this pressure would be:

2.31 ft

10 psi∗

= 23.1 ft

psi

4. Find the force on a 12-inch valve if the water pressure within the line is 60 psi. Express

your answer in tons. Solution:

Force = Pressure×Area

lbs

in²

1ton

2000lbs

=⇒ 60

∗0.785∗(12in)²∗

= 3.39 tons

10.16 Pumping Calculations

•

Pump is a machine used for moving water (and other ﬂuids) through a piping system and

raise the pressure of the water.

•

Pumping is accomplished by transforming the input energy - typically from an electric

motor or from other sources such as high-pressure air.

• The pump calculations in this section are for electrically driven rotodynamic pumps.

• To move water, a pump will need to overcome resistance due its density, gravitational force

and friction.

• This resistance is dependent on:

–

Height the water needs to be raised. This height of the ﬂuid in a container is referred

to as head.

– Quantity of water involved

10.16.1 Glossary of Pump Calculations Terms

Static Pressure: Static implies a non-moving condition. The pressure measured when there

is no water moving in a line or the pump is not running is called static ³²pressure. This is the

pressure represented by the gauges on the tanks in the discussion above.

Dynamic Pressure: When water is allowed to run through a pipe and the pressure (called pres-

sure head) measured at various points along the way we ﬁnd that the pressure decreases the

further we are from the sources.

300

Chapter 10. Water Math

Headloss: The reason for this reduction in pressure is a phenomenon called headloss. Headloss

is the loss of energy (pressure) due to friction. The energy is lost as heat.

If the headloss in a certain pipe is 25 feet, it means the amount of energy required to overcome

the friction in the pipe is equivalent to the amount of energy that would be required to lift this

amount of water straight in the air 25 feet.

In a pipe, the factors that contribute to headloss include the following:

• Roughness of pipe - If the roughness of a pipe were doubled the headloss would double.

• Length of pipe - If the length of the pipe were doubled the headloss would double.

• Diameter of pipe - If the diameter of a pipe were doubled the headloss would be cut in half

•

Velocity of water - If the velocity of the water in a pipe were doubled the headloss would

be increased by about four times. It should be apparent that velocity, more than any other

single factor, affects headloss. To double the velocity we would have to double the ﬂow in

the line.

•

Pumping System Components and Fittings - Each type of ﬁtting has a speciﬁc headloss

depending upon the velocity of water through the ﬁtting. For instance the headloss though

a check valve is two and one quarter times greater than through a ninety degree elbow and

ten times greater than the headloss through an open gate valve.

Static Head: Static head is the distance between the suction and discharge water levels when

the pump is shut off.

Suction Lift: Suction lift is the distance between the suction water level and the center of the

pump impeller. This term is only used when the pump is in a suction lift condition. A pump is

said to be in a suction lift condition any time the eye (center) of the impeller is above the water

being pumped.

Velocity Head: The amount of energy required to bring a ﬂuid from standstill to its velocity.

For a given quantity of ﬂow, the velocity head will vary indirectly with the pipe diameter.

Total Dynamic Head (TDH): The total energy needed to move water from the center line of a

pump (eye of the ﬁrst impeller of a lineshaft turbine) to some given elevation or to develop some

given pressure. This includes the static head, velocity head and the headloss due to friction.

Horsepower: Horsepower is a measurement of the amount of energy required to do work. Mo-

tors are rated in horsepower. The horsepower of an electric motor is called brake horsepower.

The horsepower requirements of a pump are dependent on the ﬂow and the total dynamic head.

33,000 foot pounds per minute of work is 1 horsepower.

Suction Head: Suction head is the distance between the suction water level and the center

of the pump impeller when the pump is in a suction head condition. A pump is said to be in a

suction head condition any time the eye (center) of the impeller is below the water level being

pumped.

Velocity Head: Velocity head is the amount of energy required by the pump and motor to over-

come inertia and bring the water up to speed. Velocity head is often shown mathematically as

V²/2 g. ( g is the acceleration due to gravity −32.2ft/sec²).

10.16 Pumping Calculations

301

Total Dynamic Head: Total dynamic head (TDH) is a theoretical distance. It is the static head,

velocity head and headloss required to get the water from one point to another.

The horsepower output of an electric motor is directly reﬂected to the amperage that the motor

draws. Any increase in horsepower requirements will give a corresponding increase in amperage.

Cavitation: Cavitation in pumps is the rapid creation and subsequent collapse of air bubbles

occuring as a result of the inlet pressure falling below the design inlet pressure or when the

pump is operating at a ﬂow rate higher than the design ﬂow rate. This collapse of the air bubbles

typically manifests as a pinging or crackling noise. Cavitation is undesirable because it can

damage the impeller, cause noise and vibration, and decrease pump efﬁciency.

302

Chapter 10. Water Math

10.16.2 Pumping Rate Calculations

•

For calculating volume pumped given the pump ﬂow rate: Multiply the pump ﬂow rate by

the time interval

Make sure:

– The time units - in the given time interval and in the pump ﬂow rate match

• For calculating time to pump a certain volume:

Step 1. Calculate the total volume pumped

Step 2. Divide the total volume by the pump ﬂow rate

Make sure:

–

The volume units - in the volume that needs to be pumped and in the pump ﬂow rate

match

–

The time unit in the pump ﬂow rate needs to be converted to the time unit that you

need the answer in

Example Problems:

1. A pump is set to pump 5 minutes each hour. It pumps at the rate of 35 gpm. How many

gallons of water are pumped each day?

Solution:

ꢁ

35 gal sludge 5 min 24 hr

4,200 gallons

ꢁ

∗

ꢁ

min

day

ꢁ

2. A pump operates 5 minutes each 15 minute interval. If the pump capacity is 60 gpm, how

many gallons are pumped daily?

H¨

60 gal sludge 5 min

min

28,800 gal sludge

¨H

∗

∗1440

H¨

min

¨H

15 min

day

3. Given the tank is 10ft wide, 12 ft long and 18 ft deep tank including 2 ft of freeboard when

ﬁlled to capacity. How much time (minutes) will be required to pump down this tank to a

depth of 2 ft when the tank is at maximum capacity using a 600 GPM pump

Solution:

2’ Freeboard

16’ Water Depth (Initial)

2’ Water Depth (Final)

10’ Wide

12’ Long

Volume to be pumped=12 ft ∗10 ft ∗(16−2) ft = 1,680ft³

ꢁ

gal

1,680ft³∗7.48

ꢁ

ft³

=⇒

= 21min

ꢁ

gal

ꢁ

600

min

10.16 Pumping Calculations

303

10.16.3 Power Requirements for Pumping

Where:

•

Input Hp is the input power to the motor which produces the Output Hp or Brake Hp -

the mechanical power which runs the pump.

• The ratio of Output Hp and Input Hp is the motor efﬁciency - η_m.

• The Output Hp is the input power (Brake Hp) to the pump to pump the water.

•

Water Hp is the rate of energy transferred to the water being pumped and can be calculated

by the formula:

H − Head of water (ft) ∗ Q − Flow (GPM)

3,960 (Conversion factor for converting GPM−ft to Hp)

• The ratio of Output Hp and Water Hp is the pump efﬁciency - η_p.

Example Problems:

1. 1 MGD is pumped against a 14’ head. What is the water Hp? The pump mechanical efﬁ-

ciency is 85%. What is the brake horsepower?

water Hp = ﬂow * head

1,000,000 gal

day

1440 min

∗

∗14 ft ∗

= Water Hp = 2.46 Hp

day

3,960 GPM − ft

pump Hp = brake Hp * pump efﬁciency

2.46

0.85

Brake Hp =

= Brake Hp = 2.89Hp

2. A ﬂow of 200 gpm is pumped against a total head of 4.0 feet. The pump is 78% efﬁcient

and the motor’ is 90% efﬁcient. Calculate the input Hp.

water Hp = ﬂow * head

200GPM ∗4 ft ∗

= 0.2Hp

3,960GPM − ft

water Hp=brake Hp*pump efﬁciency, and

brake Hp=input Hp*motor efﬁciency

Therefore, water Hp=input Hp*motor efﬁciency*pump efﬁciency

304

Chapter 10. Water Math

water Hp

0.2

input Hp=

= 0.28Hp

motor e f ficiency∗ pump e f ficiency 0.9∗0.78

10.17 Well Hydraulics Calculations

The amount of water a well will produce depends mainly on the type of aquifer, well construc-

tion, and the depth of the zone of saturation. The annual recharge rate from percolation, along

with the ability of the water bearing formation to transmit water to any given point, will also

inﬂuence well production. The performance of a well can be determined by taking readings of

the hydraulic conditions. An operator must be familiar with these terms and deﬁnitions*, in order

to accurately troubleshoot problems that may be discovered.

Static level is the water level in a well when the pump is not operating.

Pumping level is the water level in the well when it is producing.

Drawdown is the difference in elevations between the static level and the pumping level. The

amount of water produced is approximately proportional to the draw-down. For example, increas-

ing the yield by 10% will increase the drawdown by 10%. The draw-down that occurs when a

well is running is roughly equal to the head loss encountered in moving the water into the well.

Water bearing formations of gravel, limestone and course sand will usually provide more water

with less draw-down than formations containing ﬁne sand or clay.

Speciﬁc capacity is the relationship between the yield of a well and the amount of drawdown in

the well. It can be expressed as a ratio of the yield, in terms of gallons per minute, to the draw-

down in feet. A well producing 100 gpm with a drawdown of 20 feet would have a speciﬁc

capacity of 5 gpm per foot of draw-down. In this particular case every time the yield is increased

by 5 gpm the drawdown will increase by one foot. This relationship will exist until the yield

exceeds the aquifer’s ability to deliver water to any single point, When this limit is reached, the

draw-down increases dramatically with little or no increase in the yield.

Cone of depression is directly related to the drawdown in the well. As the pump draws down the

water level, a portion of the aquifer surrounding the well is drained of water. A cone shaped de-

pression is formed in the water table around the well. The shape of the cone will vary depending

10.18 Sedimentation

305

on the type of formation in which the well is located. A ﬁne sand formation will usually cre-

ate a steep cone of depression, while a shallow cone is usually found in coarse sand and gravel

formations.

Radius of inﬂuence is the farthest distance from the well that the cone of depression affects the

water table. This distance can be determined by sinking test holes around the well and monitor-

ing the water levels in them while the well is pumping.

Recovery time is the amount of time required for the aquifer to stabilize at its static water level

once pumping has stopped. This can also be determined by monitoring the water levels in the

test holes used to determine the radius of inﬂuence.

Example Problems:

1. A well is drilled through an unconﬁned aquifer. The top of the aquifer is 80 feet below

grade. After the well was in service for a year, the water level in the well stabilized at 110

feet below grade. What is the drawdown?

Drawdown = Static Level− Pumping Level = 80ft−110ft = 30feet

2. A well produces 300 gpm. If the drawdown is 30 feet, ﬁnd the speciﬁc yield.

Yield

Drawdown

300gpm

30ft

Speciﬁc Yield =

= 10gpm/ft

3. The speciﬁc yield for a well is 10gpm/ft. If the well produces 550gpm, what is the draw-

down?

Yield

Drawdown

550gpm

Drawdown

550

Speciﬁc Yield =

=⇒ 10gpm/ft =

=⇒ Drawdown =

55ft

4. The pumped water level of a well is 400 feet below the surface. The well produces 350

gpm. If the aquifer level is 250 feet below the surface, what is the speciﬁc yield for the

well?

Drawdown = Static Level− Pumping Level = 400ft−350ft = 50feet

Yield

Drawdown

350gpm

Speciﬁc Yield =

= 7gpm/ft

10.18 Sedimentation

Sedimentation calculations include the following:

1. Tank Volume

For rectangular sedimentation basins use the following equation:

Volume, gal = Length, ft∗ Width, ft∗ Depth, ft∗7.48gal/ft³

Example Problem:

1. A sedimentation basin is 25ft wide by 80ft long and contains water to a depth of 14ft

What is the volume of water in the basin, in gallons?

Volume, gal = Length, ft∗ Width, ft∗ Depth, ft∗7.48gal/ft³

Volume, gal = 80ft∗25ft∗14ft∗7.48gal/ft³

306

Chapter 10. Water Math

Volume, gal = 209,440gal

For circular clariﬁers, use the following equation:

Volume, gal = 0.785∗( Diameter )²∗ Depth, ft∗7.48gal/ft³

Example Problem:

1. A clariﬁer has a diameter of 25ft and contains water to a depth of 18ft. What is the

volume of water in the basin, in gallons?

Volume, gal = 0.785∗( Diameter )²∗ Depth, ft∗7.48gal/ft³

Volume, gal = 0.785∗(25ft)²∗18ft∗7.48gal/ft³

Volume, gal = 66,058gal

2. Detention Time

Detention time is the length of time that water stays in the sedimentation tank is called

the detention time. It is also the time it takes for a unit volume of water to pass entirely

through the clariﬁer. Additionally, detention time is also the time it would take to ﬁll an

empty clariﬁer at a given ﬂow rate.

Clari fier volume(cu. ft or gal)

Influent flow (cu. ft or gal)/hr)

Clari fier detention time (hr) =

Rectangular clariﬁer volume = width * length * depth of water

Circular clariﬁer volume = 0.785 * Diameter²* depth of water

Typically volume is calculated in cu. ft and inﬂuent ﬂow is given in gallons. Use 7.48

gal/ft³conversion factor to convert volume in cu. ft to gallons.

Example Problems:

1. A sedimentation tank has a volume of 137,000 gal. if the ﬂow to the tank is 121,000gph

what is the detention time in the tank, in hours?

Volume of tank, gal

Flow rate, gph

137,000gal

121,000gph

Detention time (hrs=

= 1.1hr

2. A sedimentation basin is 60 ft long by 22 ft wide and has water to a depth of 10 ft.

If the ﬂow to the basin is 1,500,000gpd, what is the sedimentation basin detention

time?

Volume of tank, gal

Flow rate, gph

Length, ft∗ Width, ft∗ Depth, ft∗7.48gal/ft³

Detention time, hr =

flow gal/hr

7.48gal

60ft ∗22ft ∗10 ft ∗

ft³

Detention Time =

= 1.6 hrs

1,500,000gal

day

24hours

∗

day

3. Surface Overﬂow Rate

The hydraulic or surface loading rate measures how rapidly water moves through the clari-

ﬁer. It is measured in terms of the number of gallons ﬂowing each day through one square

10.19 Filtration

foot surface area of the clariﬁer.

Clari fier hydraulic loading

307

ꢂ

ꢃ

gpd

ft²

Clari fier in fluent flow(gpd)

Clari fier sur face area(ft²)

Rectangular clariﬁer surface area = width * length

Circular clariﬁer surface area = 0.785 * Diameter²

Example Problems:

1. A circular clariﬁer has a diameter of 80ft. If the ﬂow to the clariﬁer is 1800 gpm,

what is the surface overﬂow rate in gpm/sq.ft ?

*Remember that the area of a circular clariﬁer can be determined by 0.785∗ (Diame-

ter) ²

Flow, gpm

Area, ft²

1800gpm

Surface overﬂow rate =

= 0.36gpm/ft²

0.785∗(80ft)²

2. A sedimentation basin 70ft by 25ft receives a ﬂow of 1000gpm. What is the surface

overﬂow rate in gpm/sq. ft ?

*Remember that the area of a rectangle can be found by length,ft x width, ft

Flow, gpm

Area, ft²

1000gpm

70ft∗25ft

Surface overﬂow rate =

= 0.6gpm/ft²

4. Weir Loading Rate (Overﬂow Rate) The weirs at the end of the clariﬁer allow for the

even distribution of the the outlet ﬂow across the entire length of the weir. An adequate

length of weir is needed to ensure smooth and even ﬂow of water over the weirs. Weir

overﬂow rate measures the number of gallons of water per day (or per minute) ﬂowing

over one foot of weir.

ꢂ

ꢃ

ꢂ

ꢃ

gpd or gpm

Clari fier in fluent flow(gpd)

Total e f fluent weir length (ft)

Weir over flow rate

Circular

clariﬁer weir length = 3.14 * Diameter

Example Problem:

1. A circular clariﬁer receives a ﬂow of 3.55 MGD. If the diameter of the weir is 90ft

what is the weir loading rate in gpm/sq. ft ?

ꢂ

ꢃ

ꢂ

ꢃ

gpd or gpm

Clari fier in fluent flow(gpd)

Total e f fluent weir length (ft)

Weir over flow rate

3.55MG 1,000,000gal

day

1440min

∗

= 2,465gpm

day

= 8.7gpm/ ft

3.14∗90 ft

10.19 Filtration

1. Filter Flow Rates – the ﬂow rate expressed in gpm can be calculated from the total ﬂow

over certain time or vice-versa can be used for determining either the time it would take to

process a certain ﬂow or calculate the total ﬂow.

Example Problems:

1. A ﬁlter box is 20 ft by 30 ft (including the sand area). If the inﬂuent valve is shut, the

308

Chapter 10. Water Math

water drops 3 inches per minute. What is the rate of ﬁltration in MGD?

Solution:

3in

min 12in

Water passing through the ﬁlter - Rate of Filtration (ft³/min) = 600ft²∗

∗

150ft³

min

150ft³7.48gal

1,000,000gal

1440min

ꢁ

=⇒ Rate ofFiltration(MGD) =

1.62MGD

∗

ꢁ

ft³

min

day

ꢁ

2. The ﬂow rate through a ﬁlter is 4.25 MGD. What is this ﬂow rate expressed as gpm?

Flow rate, gpd

Flowrate,gpm =

1440 min/day

Note: We are assuming that the ﬁlter operated uniformly over that 24 hour period.

gal

4.25

∗1,000,000

day

Flowrate,gpm =

= 2,951 gpm

min

1440

day

3. At an average ﬂow rate of 4000 gpm, how long of a ﬁlter run, in hours, would be

required to produce 25 MG of ﬁltered water?

Total flow (gal)

Flow rate (gpm) =

Filter run time (min)

Total flow (gal)

=⇒ Filter run time (min) =

Flow rate (gpm)

ꢁ

1,000,000 gal

min

ꢁ

=⇒ Filter run time (hr) = 25 MG ∗

104 hrs

∗

∗ 60

min

ꢁ

4,000 gal

ꢁ

2. Filtration Rates – It is the gallons of water ﬁltered per minute through each square foot of

ﬁlter area. It generally ranging from 2 to 10gpm/ft².

Filtration rate is determined by the following equation:

Flow rate, gpm

Filtration rate, gpm/ft²=

Filter surface area, ft²

Example Problems:

1. A ﬁlter 28ft long by 18ft wide treats a ﬂow of 3.5MGD. What is the ﬁltration rate in

gpm/ft ²?

Approach: The ﬂow will need to be converted to gpm and the surface area calculated

in feet.

day

3.5 MG 1,000,000 gal

∗

1440min

day

Filtration rate, gpm/ft²=

= 4.8 gpm/ ft²

28 ft ∗18 feet

2. A ﬁlter is 40ft long by 20ft wide. During a test of ﬂow rate, the inﬂuent valve to the

ﬁlter is closed for 6 minutes. The water level drop during this period is 16 inches.

10.19 Filtration

What is the ﬁltration rate for the ﬁlter in gpm/ft²?

309

Note: The volume of the water dropped after the inlet valve was closed would be the

ﬁlter ﬂow rate. Since the dimensions to calculate are in feet and inches, the volume

needs to be converted from ft³to gallons

12 in

gal

ft³

(40ft∗20ft∗16in∗

)ft³∗7.48

Filtration rate, gpm/ft²=

= 1.7 gpm/ ft²

40 ft ∗20 feet

3. Backwashing Rates - is the amount of water, in gallons, required for each backwash. This

is analogous to the Filter Flow Rate.

Example Problem:

1. A ﬁlter has the following dimensions: 30ft long by 20ft wide with a depth of 24

inches of ﬁlter media. Assuming that a backwash rate of 15gal/ft²/min is recom-

mended and 10 minutes of backwash is required, calculate the amount of water, in

gallons, required for each backwash.

The backwashing rate given in gal/ ft²/min will need to be converted into gallons by

multiplying it with the area (to eliminate ft²and by the backwash time in minutes

gal

Backwashing rate (gal) = 15

∗(30ft∗20ft)ft ∗10 min = 90,000 gal

ft −min

4. Backwash Rinse Rates - it is the upward velocity of the water during backwashing, ex-

pressed as in/min rise. To convert from gpm/ft²backwash rate to an in/min rise rate, use

either of the following equations:

Backwash rate, gpm/ft²∗12in/ft

Backwash rinse rate, in/min =

7.48gal/ft³

Example Problems:

1. A ﬁlter 22ft long by 12ft wide has a backwash rate of 3260gpm. What is this back-

wash rate expressed as a in/min rise?

Backwash rate, gpm/ft²∗12in/ft

Backwash rinse rate, in/min =

7.48gal/ft³

Based upon the above formula, the Backwash tate in gpm/ ft²needs to be calculated

by dividing the gpm ﬂow by the surface area

3260gpm

gpm/ft²∗12in/ft

22ft∗12ft

Backwash Rinse Rate, in/min =

= 19.7in/min

7.48gal/ft³

5. Percent Product Water Used for Backwashing - the equation for percent of product

water used for backwashing calculations used is:

Backwash water, gal

Backwash water, % =

∗100

Water ﬁltered, gal

Example Problems:

1. A total of 11,400,000 gal of water was ﬁltered during a ﬁlter run. If backwashing

used 48,500 gal of this product water, what percent of the product water is used for

310

Chapter 10. Water Math

backwashing?

48,500 gal

11,400,000 gal

Backwash water, % =

∗100 = 0.43%

Chapter Assessment

Practice Problems - Fractions

1. Convert 22 into a fraction

2. Express 10ft, 6in into fraction

3. Express 10ft, 6in into decimal

Practice Problems - Decimals and Powers of Ten

1. Write the equivalent of 10,000,000 as a power of ten

2. Find the product of 3.4564∗10²

3. Find the product of 534.567∗10⁻²

165.93

4. Find the value of

10⁻²

5. Find the value of 0.023∗10⁴

Practice Problems - Rounding and Signiﬁcant Digits

Round the following to the nearest hundredths (the second place after the decimal).

A. 2.4568

B. 27.2534

C. 128.2111

312

Chapter 10. Water Math

D. 364.8762

E. 354.777777

F. 34.666666

G. 67.33333

Round the following to the nearest tenths (the ﬁrst place after the decimal).

A. 2.4568

B. 27.2534

C. 128.2111

D. 364.8762

E. 354.777777

F. 34.666666

G. 67.33333

Round the following answers off to the most signiﬁcant digit.

Problem

Accurate Answer

A. 25.1+26.43

B. 128.456−121.4

C. 85−7.924328

D. 8.564+5

Problem

Accurate Answer

A. 26.34×124.34567

B. 23.58×34.251

C. 12,453/13.9

D. 12,457.92×3

Practice Problems - Totalizing and Averages

1. Find the average of the following set of numbers:

0.2

0.1

0.3

0.2

0.4

0.6

0.1

0.3

10.19 Filtration

313

2. The chemical used for each day during a week is given below. Based on these data, what

was the average lb/day chemical used during the week?

Monday

Tuesday

92 lb/day

93 lb/day

Wednesday 98 lb/day

Thursday

Friday

93 lb/day

89 lb/day

93 lb/day

97 lb/day

Saturday

Sunday

3. The average chemical use at a plant is 77 lb/day. If the chemical inventory is 2800 lbs, how

many days supply is this?

4. A well pumped for 45 days. The beginning gallon meter reading was 7,456,400 and 45

days later the same meter was 15,154,400. What was the average ﬂow in gallons per day?

Practice Problems - Percentage

1. 25% of the chlorine in a 30-gallon vat has been used. How many gallons are remaining in

the vat?

2. The annual public works budget is $147,450. If 75% of the budget should be spent by the

end of September, how many dollars are to be spent? How many dollars will be remain-

ing?

3. A 75 pound container of calcium hypochlorite has a purity of 67%. What is the actual

weight of the calcium hypochlorite in the container?

4. 3/4 is the same as what percentage?

5. A 2% chlorine solution is what concentration in mg/L ?

6. A water plant produces 84,000 gallons per day. 7,560 gallons are used to backwash the

ﬁlter. What percentage of water is used to backwash?

7. The average day winter demand of a community is 14,500 gallons. If the summer demand

is estimated to be 72% greater than the winter, what is the estimated summer demand?

Demand - When related to use, the amount of water used in a period of time. The term is

in reference to the "demand" put onto the system to meet the need of customers.

8. The master meter for a system shows a monthly total of 700,000 gallons. Of the total wa-

ter, 600,000 gallons were used for billing. Another 30,000 gallons were used for ﬂushing.

On top of that, 15,000 gallons were used in a ﬁre episode and an estimated 20,000 gallons

were lost to a main break that was repaired that same day. What is the total unaccounted

for water loss percentage for the month?

9. Your water system takes 75 coliform tests per month. This month there were 6 positive

samples. What is the percentage of samples which tested positive?

314

Chapter 10. Water Math

Practice Problems - Ratio and Proportion

1. It takes 6 gallons of chlorine solution to obtain a proper residual when the ﬂow is 45,000

gpd. How many gallons will it take when the ﬂow is 62,000 gpd?

2. A motor is rated at 41 amps average draw per leg at 30Hp. What is the actual Hp when the

draw is 36 amps? C.

3. If it takes 2 operators 4.5 days to clean an aeration basin, how long will it take three opera-

tors to do the same job?

4. It takes 3 hours to clean 400 feet of collection system using a sewer ball. How long will it

take to clean 250 feet?

5. It takes 14 cups of HTH to make a 12% solution, and each cup holds 300 grams. How

many cups will it take to make a 5% solution?

6. A bike travelling at 5 miles/hr completes a journey in 40 minutes. How long would the

same journey take if the speed was increased to 8 miles/hr?

7. Water is ﬂowing at a velocity of 1.3ft/sec in a 4.0 -in. diameter pipe. If the pipe changes

from the 4.0-inch to a 3.0-in. pipe, what will the velocity be in the 3.0-in. pipe?

Practice Problems - Area and Volume

1. A 60-foot diameter tank contains 422,000 gallons of water. Calculate the height of water in

the storage tank.

2. What is the volume of water in ft³, of a sedimentation basin that is 22 feet long, and 15 feet

wide, and ﬁlled to 10 feet?

3. What is the volume in ft³of an elevated clear well that is 17.5 feet in diameter, and ﬁlled to

14 feet?

4. What is the area of the top of a storage tank that is 75 feet in diameter?

5. What is the area of a wall 175ft. in length and 20ft. wide?

6. You are tasked with ﬁlling an area with rock near some of your equipment. 1 Bag of rock

covers 250 square feet. The area that needs rock cover is 400 feet in length and 30 feet

wide. How many bags do you need to purchase?

7. How many gallons of paint will be required to paint the walls of a 40 ft long x 65 ft wide

x 20 ft high tank if the paint coverage is 150 sq. ft per gallon. Note: We are painting walls

only. Disregard the ﬂoor and roof areas.

8. A new 24" diameter pipe is to be installed with a pipe depth, to top of pipe, of 48" and

a length of 12,000 feet The trench will be backﬁlled with sand. The trench walls will be

excavated one foot wider than the pipe on each side and six inches below the pipe. How

much excavated material must be hauled away?

9. A chemical feed pump with a 6-inch bore and a 6-inch stroke pumps 60 cycles per minute.

Find the pumping rate in gpm.

10.19 Filtration

315

Practice Problems - Flow and Velocity

1. Flow in an 8-inch pipe is 500 gpm. What is the average velocity in ft/sec? (Assume pipe is

ﬂowing full)

2. A pipeline is 18” in diameter and ﬂowing at a velocity of 125 ft. per minute. What is the

ﬂow in gallons per minute?

3. The velocity in a pipeline is 2 ft./sec. and the ﬂow is 3,000 gpm. What is the diameter of

the pipe in inches?

4. Find the ﬂow in a 4-inch pipe when the velocity is 1.5 feet per second.

5. A 42-inch diameter pipe transfers 35 cubic feet of water per second. Find the velocity in

ft/sec.

6. A plastic ﬂoat is dropped into a channel and is found to travel 10 feet in 4.2 seconds. The

channel is 2.4 feet wide and 1.8 feet deep. Calculate the ﬂow rate of water in cfs.

7. A channel is 3.25 feet wide and is conveying a a ﬂow of 3.5 MGD. The depth of the water

is 8 inches. Calculate the velocity of this ﬂow.

Practice Problems - Unit Conversions

Convert the following:

1. Convert 1000 ft³to cu. yards

2. Convert 10 gallons/min to ft³/hr

3. Convert 100,000 ft³to acre-ft.

4. Find the ﬂow in gpm when the total ﬂow for the day is 65,000 gpd.

5. Find the ﬂow in gpm when the ﬂow is 1.3cfs.

6. Find the ﬂow in gpm when the ﬂow is 0.25cfs.

7. The ﬂow rate through a ﬁlter is 4.25 MGD. What is this ﬂow rate expressed as gpm?

8. After calibrating a chemical feed pump, you’ve determined that the maximum feed rate is

178 mL/ minute. If this pump ran continuously, how many gallons will it pump in a full

day?

9. A plant produces 2,000 cubic foot of water per hour. How many gallons of water is pro-

duced in an 8-hour shift?

10. Change 70 °F to °C

11. Change 4 °C to °F

Practice Problems - Concentration

1. How many lbs of salt needs to be dissolved in water to make 1 liter of 5% salt solution?

2. What is the concentration in mg/l of 4.5% solution of that substance.

3. An operator mixes 40 lb of lime in a 100-gal tank containing 80 gal of water. What is the

percent of lime in the slurry?

316

Chapter 10. Water Math

4. An operator mixes 40 lb of lime in a 100-gal tank containing 80 gal of water. What is the

percent of lime in the slurry? Solution:

40 lbs lime

1,000,000 lbs

million lbs

∗

lbs

10,000 ppm

80 gal water ∗8.34

+40 lbs lime

gal water

5.7%

Practice Problems - Density and Speciﬁc Gravity

1. What is the speciﬁc gravity of a 1 ft³concrete block which weighs 145 lbs?

2. What is the speciﬁc gravity of a chlorine solution if 1 (one) gallon weighs 10.2lbs?

3. How much does each gallon of zinc orthophosphate weigh (pounds) if it has a speciﬁc

gravity of 1.46?

4. How much does a 55 gallon drum of 25% caustic soda weigh (pounds) if the speciﬁc

gravity is 1.28?

Practice Problems - Pounds Formula

1. A water treatment plant operates at the rate of 75 gallons per minute. They dose soda ash

at 14 mg/L. How many pounds of soda ash will they use in a day?

Practice Problems - Chemical Dosing

1. In order to disinfect a sedimentation basin measuring 20ft in width, 60 feet in length, and

is 10 feet deep to obtain 50ppm would require how many lbs. of 65% available HTH ?

2. Determine the chlorinator setting (lb/day) required to treat a ﬂow of 4MGD with a chlorine

dose of 5mg/L.

3. A pipeline that is 12 inches in diameter and 1400ft long is to be treated with a chlorine

dose of 48mg/L. How many lb of chlorine will this require?

4. What should the chlorinator seting be (lb/day) to treat a ﬂow of 2.35MGD if the chlorine

demand is 3.2mg/L and a chlorine residual of 0.9mg/L is desired?

5. A water treatment plant operates at the rate of 75 gallons per minute. They dose soda ash

at 14 mg/L. How many pounds of soda ash will they use in a day?

6. A water treatment plant is producing 1.5 million gallons per day of potable water, and uses

38 pounds of soda ash for pH adjustment. What is the dose of soda ash at that plant?

7. A water treatment plant produces 150,000 gallons of water every day. It uses an average

of 2 pounds of permanganate for iron and manganese removal. What is the dose of the

permanganate?

8. A water treatment plant uses 8 pounds of chlorine daily and the dose is 17 mg/l. How

many gallons are they producing?

10.19 Filtration

317

Practice Problems - Blending and Dilution

1. Ferric chloride is being added as a coagulant to the raw water entering a plant. Sampling

shows that the concentration of ferric in the raw water is 25 ppm. A quick check of the

chemical metering pump shows that it is operating at a ﬂow rate of 4.3 gpm. If the ﬂow

through the water plant is 800 gpm, what is the concentration of raw chemical in the dos-

ing tank?

2. A water plant is fed by two different wells. The ﬁrst well produces water at a rate of 600

gpm and contains arsenic at 0.5 mg/L. The second well produces water at a rate of 350

gpm and contains arsenic at 12.5 mg/L. What is the arsenic concentration of the blended

water?

Practice Problems - Pumping Rates

1. How long will it take (hrs) to ﬁll a 2 ac-ft pond if the pumping rate is 400 GPM?

2. A pump is set to pump 5 minutes each hour. It pumps at the rate of 35 gpm. How many

gallons of water are pumped each day?

3. A pump operates 5 minutes each 15 minute interval. If the pump capacity is 60 gpm, how

many gallons are pumped daily?

4. Given the tank is 10ft wide, 12 ft long and 18 ft deep tank including 2 ft of freeboard when

ﬁlled to capacity. How much time (minutes) will be required to pump down this tank to a

depth of 2 ft when the tank is at maximum capacity using a 600 GPM pump

Practice Problems - Pressure, Force and Head Relationship

1. A 42-inch main line has a shut off valve. The same line has a 10-inch bypass line with

another shut-off valve. Find the amount of force on each valve if the water pressure in the

line is 80 psi. Express your answer in tons.

2. A water tank is 15 feet deep and 30 feet in diameter. What is the force exerted on a 6-inch

valve at the bottom of the tank?

3. A water tank is ﬁlled to depth of 22 feet. What is the psi at the bottom of the tank?

4. The static pressure in a water main is 85 psi. What elevation of water is needed to provide

that kind of pressure?

5. The pressure at the top of the hill is 62 psi. The pressure at the bottom of the hill, 60 feet

below, is 100 psi. The water is ﬂowing uphill at 120 gpm. What is the friction loss, in feet,

in the pipe?

318

Chapter 10. Water Math

Practice Problems - Pumping Power Requirements

1. If a pump is operating at 2,200 gpm and 60 feet of head, what is the water horsepower? If

the pump efﬁciency is 71%, what is the brake horsepower?

2. The water horsepower of a pump is 10Hp and the brake horsepower output of the motor is

15.4Hp. What is the efﬁciency of the pump?

3. The water horsepower of a pump is 25Hp and the brake horsepower output of the motor is

48Hp. What is the efﬁciency of the pump?

4. The efﬁciency of a well pump is determined to be 75%. The efﬁciency of the motor is

estimated at 94%. What is the efﬁciency of the well?

5. If a motor is 85% efﬁcient and the output of the motor is determined to be 10 BHp, what is

the electrical horsepower requirement of the motor?

6. The water horsepower of a well with a submersible pump has been calculated at 8.2 WHp.

The Output of the electric motor is measured as 10.3BHp. What is the efﬁciency of the

pump?

7. Water is being pumped from a reservoir to a storage tank on a hill. The elevation difference

between water levels is 1200 feet. Find the pump size required to ﬁll the tank at a rate of

120 gpm. Express your answer in horsepower.

A 25hp pump is used to dewater a lake. If the pump runs for 8 hours a day for 7 days a

week, how much will it cost to run the pump for one week? Assume energy costs $0.07

per kilowatt hour.

9. A pump station is used to lift water 50 feet above the pump station to a storage tank. The

pump rate is 500gpm. If the pump has an efﬁciency of 85% and the motor has an efﬁ-

ciency of 90%, ﬁnd each of the following: Water Horsepower, Brake Horsepower, Motor

Horsepower, and Wire-to-Water Efﬁciency.

10. Find the brake horsepower for a pump given the following information: Total Dynamic

Head = 75 feet, Pump Rate = 150 gpm, Pump Efﬁciency = 90%, Motor Efﬁciency = 85%

11. Water is being pumped from a reservoir to a storage tank on a hill. The elevation difference

between water levels is 1200 feet. Find the pump size required to ﬁll the tank at a rate of

120 gpm. Express your answer in horsepower.

Practice Problems - Well Hydraulics

1. A well yields 2,840 gallons in exactly 20 minutes. What is the well yield in gpm?

2. Before pumping, the water level in a well is 15 ft. down. During pumping, the water level

is 45 ft. down. The drawdown is:

3. A well produces 365 gpm with a drawdown of 22.5 ft. What is the speciﬁc yield in gallons

per minute per foot?

4. A well is located in an aquifer with a water table elevation 20 feet below the ground sur-

face. After operating for three hours, the water level in the well stabilizes at 50 feet below

the ground surface. The pumping water level is:

10.19 Filtration

319

5. Calculate drawdown, in feet, using the following data:

The water level in a well is 20 feet below the ground surface when the pump is not in

operation, and the water level is 35 feet below the ground surface when the pump is in

operation.

6. Calculate the well yield in gpm, given a drawdown of 14.1 ft and a speciﬁc yield of 31

gpm/ft.

Practice Problems - Sedimentation

1. Calculate the detention time for a sedimentation tank that is 48 feet wide, 210 feet long

and 9 feet deep with a ﬂow of 5 MGD.

2. At a 2.5 MGD wastewater treatment plant the primary clariﬁer has a detention time of 2

hours. How many gallons does this clariﬁer hold?

3. A circular clariﬁer has a diameter of 80 ft. If the ﬂow to the clariﬁer is 1800 gpm, what is

the surface overﬂow rate in gpm/ft

4. A sedimentation basin 70 ft by 25 ft receives a ﬂow of 1000 gpm. What is the surface

overﬂow rate in gpm/ft2?

5. A circular clariﬁer receives a ﬂow of 3.55 MGD. If the diameter of the weir is 90 ft, what

is the weir loading rate in gpm/ft?

Practice Problems - Filtration

1. At an average ﬂow of 4,000 gpm, how long of a ﬁlter run in hours would be required to

produce 25 MG of ﬁltered water?

2. A ﬁlter is 40ft long by 20ft wide. During a test of ﬂow rate, the inﬂuent valve to the ﬁlter

is closed for 6 minutes. The water level drop during this period is 16 inches. What is the

ﬁltration rate for the ﬁlter in gpm/ft²?

3. A water treatment plant treats 6.0 MGD with four ﬁlters. Each ﬁlter use 60,000 gallons per

wash. What is the percent backwash at the plant?

4. A treatment plant ﬁlter washes at a rate of 10,000 GPM. The ﬁlter measures 18ft. wide by

24ft. long. What is the rate of rise expressed in inches per minute?

5. If a ﬁlter measures 20 feet by 30 feet by 7 foot deep and the backwash ﬂow is 3.5cuft/sec

what is the backwash rate?

Chapter Assessment

Solutions

11 Assessments Solutions . . . . . . . . . . . . . . 317

11.1

Chapter 2 - Properties and Sources

Chapter 3 - Water Quality and Laboratory Proce-

dures

11.2

11.3

11.4

11.5

11.6

11.7

11.8

11.9

Chapter 4 - Regulations

Chapter 5 - Treatment

Chapter 6 - Disinfection

Chapter 7 - Pumping

Chapter 8 - Distribution

Chapter 9 - Safety

Chapter 10 - Math

11. Assessments Solutions

11.1 Chapter 2 - Properties and Sources

1. Groundwaters generally have consistent water quality that include

*a. having a higher total dissolved solids content than surface water

b. having a lower mineral content than surface waters

c. having lower pH values than surface waters

d. having a higher amount of bacteria than surface waters

2. When underground water is under pressure greater than atmospheric pressure and could

rise above the its conﬁning space and above the ground level is referred to as a(n)

a. aquifer

b. anaerobic condition

*c. artesian effect

d. drawdown

e. pressure gradient

3. The gradual ﬂow or movement of water into and through the pores of the soil is called

*a. percolation

b. run-off

c. precipitation

d. impermeable ﬂow

e. evapotranspiration

4. Water that has been used to carry solids away from a home or ofﬁce into a treatment facil-

ity is referred to as

*a. wastewater or sewage

324

Chapter 11. Assessments Solutions

b. potable

c. seawater intrusion injection water

d. riparian water

5. The water right to put it to beneﬁcial use of the surface water adjacent to your land is

called water.

a. wastewater

*b. riparian

c. ﬁlter ripening

d. inﬁltration

e. run-off

6. The difference between static level and pumping level in a well is called:

*a. drawdown.

b. cone of depression

c. zone of saturation

d. radius of inﬂuence

7. Which one of the following best deﬁnes the term aquifer?

a. A low lying area where water pools

*b. Water-bearing stratum of rock, sand, or gravel

c. Impervious stratum near the ground surface

d. Treated water leaving the water system

8. The height to which water will rise in wells located in an artesian aquifer is called the

a. Pumping water level

b. Water table

*c. Piezometric surface

d. Drawdown

e. Radius of inﬂuence

9. What percentage of all the earth’s water is readily available as a potential drinking water

supply in the form of lakes, rivers, and near-surface groundwater?

a. 97

b. 50

c. 2

d. 1

*e. 0.34

10. To prevent the entry of surface contamination into a well is the purpose of

a. The well casing

b. The water table

c. The louvers or slots

d. Well development

*e. The annular grout seal

11. An aquifer that is located underneath an aquiclude is called

11.1 Chapter 2 - Properties and Sources

325

a. An unconﬁned aquifer

*b. A conﬁned aquifer

c. A water table

d. Unreachable groundwater

e. An Artesian spring

12. The process by which water changes from the gas to the liquid phase is termed

*a. Condensation ·

b. Evaporation

c. Percolation

d. Precipitation

e. Runoff

13. The free surface of the water in an unconﬁned aquifer is known as the

a. Pumping water level

b. Artesian spring

*c. Water table

d. Drawdown

e. Percolation

14. The transfer of liquid water from plants and animals on the surface of the earth into water

vapor in the atmosphere is called

* a. Transpiration

b. Evaporation

c. Condensation

d. Runoff

e. Percolation

15. The elevation of water in the casing of an operating well is called the

a. Piezometric surface

b. Water table

*c. Pumping water level

d. Drawdown

e. Radius of inﬂuence

16. An aquifer under pressure is often termed

a. Unconﬁned

b. Paciﬁc

*c. Artesian

d. Alluvial

e. Elevated

17. An aquifer is usually composed of

*a. Sand and gravel

b. Clays and silts

c. Bedrock

326

Chapter 11. Assessments Solutions

d. Large voids in the soil, resembling underground lakes

e. None of the above

18. Which of the following best deﬁnes the term speciﬁc capacity?

a. Amount of water a given volume of saturated rock or sediment will yield to gravity

b. Amount of water a given volume of saturated rock or sediment will yield to pumping

c. Rate at which water would ﬂow in an aquifer if the aquifer were an open conduit

*d. Amount of water a well will produce for each foot of drawdown

19. The most common type of well used for public water supply systems is a

a. Jetted well

*b. Driven well

c. Drilled well

d. Bored well

20. An aquifer that is underneath a layer of low permeability is known as

*a. Conﬁned aquifer

b. Water Table aquifer

c. Unconﬁned aquifer

d. Unreachable groundwater

21. What is the middle layer of a stratiﬁed lake known as?

a. Hypolimnion

b. Benthic Zone

*c. Thermocline

d. Epilimnion

22. The amount of water that can be pulled from a aquifer without depleting

a. Drawdown

*b. Safe yield

c. Overdraft

d. Subsidence

11.2 Chapter 3 - Water Quality and Laboratory Procedures

327

11.2 Chapter 3 - Water Quality and Laboratory Procedures

1. Hard water contains an abundance of

a. sodium

b. iron

c. lead

*d. calcium carbonate

2. A speciﬁc class of bacteria that only inhibit the intestines of warm-blooded animals is

referred to as?

a. Eutrophic

b. Grazing

c. Salmonella

*d. Fecal coliform

e. pathogenic

3. Water with a pH of 8.0 is considered to be

a. acidic

*b. basic or alkaline

c. neutral

d. undrinkable

4. Over which water quality indicator do operators have the greatest control?

a. alkalinity

b. pH

c. temperature

*d. turbidity

5. Which piece of laboratory equipment is used to titrate a chemical reagent?

a. graduated cylinder

*b. burette

c. pipet

d. Buchner funnel

6. Which pH range is generally accepted as most palatable (drinkable)?

*a. 6.5 to 8.5

b. 4.5 to 6.5

c. 8.5 to 9.5

d. 9.5 and above

e. all of the above

7. Which of the following conditions is favorable for the rapid growth of algae?

*a. plant nutrients

b. high pH and water hardness

c. low temperatures and low dissolved oxygen

d. high alkalinity and water hardness

328

Chapter 11. Assessments Solutions

8. Which of the following is the name given for a turbidity meter that has reﬂected or scat-

tered light off suspended particles as a measurement?

a. Hach colorimeter

b. spectrophotometer

c. Wheaton bridge

*d. Nephelometer

9. Water hardness is the measure of the concentrations of and dissolved in the water sample.

a. iron, manganese

b. nitrates, nitrites

c. sulfates, bicarbonates

*d. calcium & magnesium carbonates

e. ferric chlorides and polymers

10. The electrical potential required to transfer electrons from one compound or element to

another is commonly referred to as

*a. oxidation-reduction potential (ORP)

b. voltage potential (OHM/P)

c. resistance-impedance potential

d. microMho differential

11. Water has physical, chemical, and biological characteristics. Which of the following is a

physical characteristic?

a. Coliform

*b. Turbidity

c. Hardness

d. All the above

12. Tastes and odors in surface water are most often caused by:

a. clays

b. hardness

*c. algae

d. coliform bacteria

13. Which of the following elements cause hardness in water?

a. sodium and potassium

*b. calcium and magnesium

c. iron and manganese

d. turbidity and suspended solids

14. When measuring for free chlorine residual, which method is the quickest and simplest?

*a. DPD color comparator

b. Orthotolidine method

c. Amperometric titration

d. 1, 2 nitrotoluene di-amine method

11.3 Chapter 4 - Regulations

329

11.3 Chapter 4 - Regulations

1. Primary drinking water standards are set to protect the public from illnesses as a direct

result in drinking water that exceeds maximum set levels. Secondary standards were set to

alert the public to

a. the incidences of local cancer numbers

b. dissolved solids in water

c. immediate health concerns

d. radiological conditions concerning drinking water

*e. aesthetic issues with drinking water

2. A positive fecal coliform test must be reported to the primacy agency within

a. 8 hours.

b. 12 hours.

*c. 24 hours.

d. 48 hours.

3. Which agency sets legal limits on the concentration levels of harmful contaminants in

potable water distributed to customers?

a. National Primary Drinking Water Regulations

*b. United States Environmental Protection Agency

c. United States Public Health Service

d. Occupational Health and Safety Organization

4. Which may be substituted for the analysis of residual disinfectant concentration, when

total coliforms are also sampled at the same sampling point?

*a. Heterotrophic plate count (HPC)

b. Fecal coliforms

c. Giardia lamblia

d. Combined chlorine

5. What does the acronym MCL stand for?

a. Minimum contaminant level

b. Micron contaminant level

*c. Maximum contaminant level

d. Milligrams counted last

6. How long do sanitary surveys have to be retained for records?

a. 3 years

b. 5 years

c. 7 years

*d. 10 years

7. The most severe water system violation that requires the fastest public notiﬁcation

*a. Tier I

b. Tier II

330

Chapter 11. Assessments Solutions

c. Tier III

d. Tier IV

8. The primacy agency may grant a variance or exemption as long as

a. The agency is using the Best Available Technology

b. There is no threat to public health

c. There is never a scenario for a variance or exemption

*d. Both A. and B.

9. A public water system that serves at least 25 people six months out of the year

*a. Nontransient noncommunity

b. Transient noncommunity

c. Community public water system

d. None of the above

10. Regulations based on the aesthetic quality of drinking water

a. Primary Standards

*b. Secondary Standards

c. Microbiological Standards

d. Radiological Standards

11. The lowest reportable limit for a water sample

a. 0.5mg/1

b. Zero

c. Public health goal

*d. Reporting Detection Level

12. Primary Standards are based on

a. Color and Taste

b. Aesthetic quality

*c. Public Health

d. Odor

13. A disease causing microorganism

*a. Pathogen

b. Colilert

c. Pathological

d. Turbidity

14. According to Surface Water Treatment Rule, what is the combined inactivation and re-

moval for Giardia?

a. 1.0log

b. 2.0log

*c. 3.0log

d. 4.0 Logs

15. What is the equivalency expressed as a percentage for the SWTR inactivation and removal

of viruses?

11.3 Chapter 4 - Regulations

331

a. 99.9%

*b. 99.99%

c. 99.0%

d. 99.999%

16. A water agency that takes 40 or more of total coliform samples will trigger a monthly

MCL violation if more than

of the samples are determined to be total coliform

positive.

a. 10%

b. 7%

*c. 5%

d. No positive samples allowable

17. The National Primary Drinking Water Regulations apply to drinking water contaminants

that may have adverse effects on

a. Water color

b. Water taste

c. Water odor

*d. Human health

18. Which of the following is considered an acute risk to health?

a. Two Tier 2 violations

b. One Tier 2 violation

c. Two Tier 1 violations

*d. One Tier 1 violation

19. Records on turbidity analyses should be kept for a minimum of

*a. 5 years

b. 7 years

c. 10 years

d. 25 years

20. Records on bacteriological analyses should be kept for a minimum of

*a. 5 years

b. 7 years

c. 10 years

d. 25 years

332

Chapter 11. Assessments Solutions

11.4 Chapter 5 - Treatment

1. What is the purpose of coagulation and ﬂocculation?

a. control corrosion

b. to kill disease causing organisms

c. to remove leaves, sticks, and ﬁsh debris

*d. to remove particulate impurities and suspended matter

2. How are ﬁlter production (capacity) rates measured?

a. Mgd/sq.ft.

*b. Gpm/sq.ft.

c. Gpm

d. Mgd

3. Why should a ﬁlter be drained if it is going to be out-of-service for a prolonged period?

a. to allow the media to dry out

b. to save water

c. to prevent the ﬁlter from ﬂoating on groundwater levels

*d. to avoid algal growth

4. Which of the following are commonly used coagulation chemicals?

a. hypochlorites and free chlorine

b. sodium and potassium chlorides

*c. alum and polymers

d. bleach and HTH

5. How can an operator tell if a ﬁlter is NOT completely cleaned after backwashing?

a. the initial headloss is on the high side

*b. the backwash rate was too slow

c. mudballs are NOT present

d. backwashing pumping rate is too low

6. Flocculation is deﬁned as

*a. the gathering of ﬁne particles after coagulation by gentle mixing

b. clumps of bacteria

c. the capacity of water to neutralize acids

d. a high molecular weight of compounds that have negative charges

7. A multi-barrier water ﬁltration plant that contains a ﬂash mix, a coagulation/ﬂocculation

zone, sedimentation, ﬁltration and a clear well is considered to be a

a. community special treatment plant

b. direct ﬁltration plant

c. reverse osmosis plant

*d. conventional ﬁltration plant

e. traditional plant

8. The ﬁltration unit process usually

11.4 Chapter 5 - Treatment

333

a. is located at the beginning of a ﬁltration plant

*b. follows the coagulation/ﬂocculation/sedimentation processes

c. is located after the clear well area

d. is located on the plant efﬂuent line after the clearwell

9. Filters are generally backwashed when the loss-of-head indicator registers a certain set

value, such as 6-ft, or upon a certain time, say 48-hours, or upon a rise in

a. alkalinity

b. a jar-test result

*c. turbidity

d. temperature

10. What is a method of reducing hardness?

*a. Softening

b. Hardening

c. Lightning

d. Flashing

11. The solid that adsorbs a contaminant is called the:

*a. Adsorbent

b. Adsorbate

c. Sorbet

d. Rock

12. The adsorption process is used to remove:

*a. Organics or inorganics

b. Bugs or salts

c. Organisms or dirt

d. Color or particles

13. Describe two primary methods used to control taste and odor?

*a. Oxidation and adsorption

b. Filtration and sedimentation

c. Mixing and coagulation

d. Sedimentation and clariﬁcation

14. What is the recommended loading rate for copper sulfate for algae control at an alkalinity

greater than 50mg/L ?

a. 0.9 of copper sulfate per acre of surface area

b. 1.9 of copper sulfate per acre of surface area

c. 2-4 lb of copper sulfate per acre of surface area

*d. 5.4 of copper sulfate per acre of surface area

15. The basic goal for water treatment is to

*a. Protect public health

b. Make it clear

c. Make it taste good

334

Chapter 11. Assessments Solutions

d. Get stuff out

16. Greensand can be operated in either

modes.

regeneration or

regeneration

*a. Continuous or intermittent

b. Fast or slow

c. Hot or cold

d. Constant or unusual

11.5 Chapter 6 - Disinfection

335

11.5 Chapter 6 - Disinfection

1. The two most common types of chlorine disinfection by-products include:

*a. TTHM and HAA5

b. TTHA of HMM5

c. Turbidity and color

d. Chloride and ﬂuoride

2. Chlorine gas is times heavier than breathing air

*a. 2.5

b. 20

c. 60

d. 460

3. A commonly used method to test for chlorine residual in water is called the method.

a. HTH

b. THM

c. VOC

*d. DPD

4. When chlorine gas is added to water the pH goes down due to

a. chlorine gas producing caustic substances

b. two base materials that form

*c. two acids that form

d. caustic soda being formed in the water

5. Disinfection by-products are a product of:

a. Filtration

*b. Disinfection

c. Sedimentation

d. Adsorption

6. Chloramine is most effective as a disinfectant.

a. Primary

b. Secondary

c. Third

d. First

7. Name two methods commonly used to disinfect drinking water other than chlorination.

*a. Ozone and ultraviolet light

b. Soap and agitation

c. Filtration and adsorption

d. Salt and vinegar

8. In order to determine the effectiveness of disinfection, it is desirable to maintain a disinfec-

tant residual of at least mg/L entering the distribution system.

a. 0.10

336

Chapter 11. Assessments Solutions

b. 0.5

c. 0.3

*d. 0.2

9. Secondary disinfectants are used to provide a in the distribution system.

a. Color

b. Chemical

c. Smell

*d. Residual

10. Primary disinfectants are used to microorganisms.

a. Hurt

*b. Inactivate

c. Burn up

d. Evaporate

11. The quantity of chlorine remaining after primary disinfection is called a residual.

*a. Chlorine

b. Permaganate

c. Hot

d. Cold

12. The two most common types of chlorine disinfection by-products include:

*a. TTHM and HAA5

b. TTHA of HMM5

c. Turbidity and color

d. Chloride and ﬂuoride

13. In order to determine the effectiveness of disinfection, it is desirable to maintain a disinfec-

tant residual of at least mg/L entering the distribution system.

a. 0.10

b. 0.5

c. 0.3

*d. 0.2

14. A

a. Large

residual of chlorine is required throughout the distribution system.

b. High

*c. Trace

d. Hot

15. The test used to determine the effectiveness of disinfection is called the:

*a. Coliform bacteria test

b. Color test

c. Turbidity test

d. Particle test

16. Name two methods commonly used to disinfect drinking water other than chlorination.

11.5 Chapter 6 - Disinfection

337

a. Ozone and ultraviolet light

b. Soap and agitation

c. Filtration and adsorption

d. Salt and vinegar

17. Name the two types of hypochlorites used to disinfect water.

a. Chloride and monochloride

*b. Sodium and calcium

c. Ozone and hydroxide

d. Arsenic and manganese

18. Free chlorine can only be obtained after

chlorination has been achieved.

*a. Breakpoint

b. Fastpoint

c. Softpoint

d. Onpoint

19. The meaning of the " C" and the " T " in the term CT stands for:

*a. Concentration and time

b. Color and turbidity

c. Calcium and tortellini

d. Chlorine and turbidity

20. Chloramine is most affective as a disinfectant.

a. Primary

*b. Secondary

c. Third

d. First

21. TTHMs and HAA5s can affect:

*a. Health

b. Aesthetics

c. Color

d. Odor

338

Chapter 11. Assessments Solutions

11.6 Chapter 7 - Pumping

1. Name the type of valve that is sometimes found on the suction side of a centrifugal pump

and is located where the water enters the casing.

a. Check valve

b. Gate valve

c. Altitude valve

d. Pressure relief valve

*e. Foot valve

2. After a pump is shut off but continues to run backwards indicates:

a. The bearings are failing

b. The packing needs tightening

c. The main lock nut needs to be tightened

*d. The check valve is leaking

e. A valve on the discharge side of the pump is shut

3. Wear rings are installed in a pump to:

a. hold the shaft in position

b. keep the impeller in place

*c. keep wear concentrated on economically replaceable part

d. wear out the sleeve

4. Pump motors draw more power starting than during normal operating conditions because:

a. check valves have to be pushed open

b. energy is required to get the water moving

c. the motor and pump have to start turning

*d. all of the above

5. Head is measured in

a. absolute pressure.

b. gauge pressure.

*c. feet.

d. foot-pounds.

6. To ease installation of impeller wear rings, they can be

a. lubricated with a light oil.

b. greased with lithium.

*c. heated.

d. cooled.

7. Packing is designed to

a. add lubricant to the shaft.

b. expand and deteriorate with normal use.

c. protect the shaft.

*d. wear and deteriorate with normal use.

11.6 Chapter 7 - Pumping

339

8. Bearings on a line shaft turbine can be lubricated with

*a. oil or water.

b. grease or oil.

c. lithium or grease.

d. graphite or grease.

9. Packing replacement is usually performed when

*a. water leakage sprays out of the pump housing.

b. no further tightening can be done on the packing gland.

c. the packing gland bolts are exposed by more than 2^1/2inches above the nut.

d. the packing has completely disintegrated.

10. Which is at the top of a stufﬁng box?

*a. Packing gland

b. Lantern ring

c. Mechanical seal

d. Seal cage

11. Which assembly holds the lantern ring and packing?

a. Shaft assembly

b. Casing ring assembly

*c. Packing gland casing

d. Stufﬁng box

12. Which of the following prevents the impeller of a pump from turning on the shaft?

a. Lock nut on threaded shaft

*b. Key

c. Steel pin

d. Caliper pin

13. Which device serves the same function as the packing?

a. Inline suction gland

b. Packing gland

*c. *Mechanical seal

d. Lantern seal

14. Vertical turbine pumps that are used in wells may be oil-lubricated or water-lubricated.

Operators should use extreme care not to start any water-lubricated pump before making

sure that the:

a. Valve on discharge side is open.

b. Bearings are dry.

c. Valve on suction side is closed.

*d. Bearings are wet.

15. The head against which a pump must operate:

*a. Is the sum of the static head and the head due to friction loss.

b. Must always be above the shut-off head.

340

Chapter 11. Assessments Solutions

c. Is the static head.

d. Is the friction head.

16. What term describes the condition that exists when the source of the water supply is below

the centerline of the pump?

a. Pressure head

b. Velocity head

*c. Suction lift

d. Total discharge head

17. What is the most common use today for a positive-displacement pump?

*a. Raw water intake pump

b. System booster pump

c. Chemical feed pump

d. Filter feed pump

18. A pumping condition where the eye of the impeller is above the water is called?

a. Dry Well

b. Suction Head

c. Wet Well

*d. Suction Lift

19. The force used in an End-suction pump is called

a. Pressure

*b. Centrifugal

c. Velocity

d. Kinetic

20.

is the loss of energy as a result of friction.

a. Velocity loss

*b. Headloss

c. Elevation Loss

d. Pump Loss

21. As the water travels around the volute towards the discharge line the total energy shifts

from

a. High Velocity Head to low psi

b. Low Velocity Head to high psi

c. Low Velocity Head to low psi

*d. High Velocity Head to high psi

22. The part that in an End Suction pump that is used to collect the liquid discharged from the

impeller is called?

a. Shaft

b. Packing

c. Suction Head

*d. Volute

11.6 Chapter 7 - Pumping

341

23. Head is the energy that a body has by virtue of its position or state.

a. Velocity

*b. Potential

c. Kinetic

d. Pressure

24. An impeller that has no shrouds and used to pump ﬂuid with large objects is called?

a. Semi-open

*b. Open

c. Closed

d. Very-closed

25. A pump station design where the eye of the impeller is submerged in water is called?

a. Dry Well

b. Suction Head

*c. Wet Well

d. Suction Lift

342

Chapter 11. Assessments Solutions

11.7 Chapter 8 - Distribution

1. What is the reason for keeping adequate, reliable records in a treatment plant?

*a. to record the plant’s effectiveness and because of requirements by regulatory agencies

b. to maintain records for cold cases

c. in case the IRS wishes to check ﬁles for due diligence

d. because of homeland security issues and ﬁles being available to the public

2. Which statement about displacement meters is not correct:

a. The most common type of water service meter is the displacement type

b. Displacement meters are accurate at low ﬂows

c. Excess sediment can cause the meter to stop registering

*d. Displacement meters have little head loss due to friction

e. Displacement meters operated at a rate in excess of its stated capacity can result in

excessive wear

3. A ﬁre hydrant should be closed slowly to avoid:

a. Excessive wear

*b. Water hammer

c. Excessive head loss

d. Injury to operator

4. The minimum separation between municipal water mains and sanitary sewers for installa-

tion in a common trench shall be:

a. 5 feet horizontal separation

b. 10 feet horizontal separation

c. 15 feet horizontal separation

d. 25 feet horizontal separation

5. To properly disinfect a water main after new construction, you should:

*a. apply 50mg/l chlorine for 24 hours.

b. clean the pipe out with a pig and then disinfect at 10mg/1 for 24 hours

c. use a 10% solution of calcium chloride

d. don’t use them main for one week

6. When using a dry-barrel ﬁre hydrant, the valve:

a. should never be opened completely

b. be opened only during the hours of 8AM to 5PM

c. be opened to the desired amount of ﬂow

*d. be opened all the way

7. The primary reason for dry barrel-ﬁre hydrants is to:

a. allow easy maintenance

b. prevent water hammer

*c. keep the hydrant from freezing

d. keep the barrel from rusting

11.7 Chapter 8 - Distribution

343

8. A centrifugal pump should not be run empty except momentarily because:

a. a serious counter pressure could develop and damage the pump casing. b. it is a waste of

energy to run a pump without water.

c. the excessive end thrust of the shaft would damage the thrust bearing.

*d. the parts lubricated by water could be damaged.

9. Pipes of dissimilar metal should not be connected together because of problems due:

a. to scale formation

*b. corrosion

c. water hammer

d. the venturi effect

10. Which type of valve will prevent the collapse of a pipe?

a. Pressure-relief valve

b. Needle valve

c. Pinch valve

*d. Air-and-vacuum relief valve

11. The correct protective methods for backﬂow-prevention devices in order of decreasing

effectiveness are

a. air gap, VB, RPZ, and DCVA.

b. air gap, VB, DCVA, and RPZ.

c. air gap, RPZ, VB, and DCVA.

*d. air gap, RPZ, DCVA, and VB.

12. The C-value is a measure of a pipe’s wall

a. smoothness.

b. smoothness giving even ﬂow.

c. smoothness that retards turbulent ﬂow.

*d. roughness that retards ﬂow due to friction.

13. Which one of the following is a type of joint for ductile iron piping?

a. Expansion joint

*b. Push-on joint

c. Bell and spigot with rubber o-ring

d. Rubber gasket joint

14. Water hammer can be described as

a. particle waves.

b. acoustic waves.

c. rogue waves.

d. longitudinal waves.

15. Which thrust control is easy to use, especially in locations where existing utilities or struc-

tures are numerous?

a. Restraining ﬁttings

b. Tie rods

344

Chapter 11. Assessments Solutions

c. Thrust anchors

d. Thrust blocks

16. The backﬁll material for a pipe installation should contain enough to allow for thorough

compaction.

a. moisture

*b. sand

c. gravel

d. mixed sizes

17. Thrust from a water surge almost always acts pushes against. to the inside surface that it

*a. vertically

b. horizontally

c. perpendicular

d. vertically and horizontally

18. The breaking of a buried pipe when it is unevenly supported is called

a. stress breakage.

b. shear breakage.

*c. beam breakage.

d. ﬂexural breakage.

19. Compression ﬁttings used with copper or plastic tubing seal by means of a

*a. beveled sleeve.

b. compression ring.

c. compressed beveled gasket.

d. compressed o-rings located at either end of the ﬁtting’s beveled neck.

20. Which should be installed at a dead-end water main?

a. Vacuum valve

b. Air valve

*c. Blowoff valve

d. Water quality sampling station

21. First draw samples for the analysis of lead and copper water must be collected from taps

where the water has stood motionless in the plumbing for at least

a. 4 hours.

b. 6 hours.

c. 8 hours.

*d. 24 hours.

22. According to AWWA Standard C651, disinfection of water mains requires 24-hour expo-

sure to which minimum free chlorine residual?

a. 10mg/L

*b. 25mg/L

c. 50mg/L

d. 100mg/L

11.7 Chapter 8 - Distribution

345

23. The tensile strength of a pipe is its ability to

*a.Stretch or pull without breakage

b. Resist internal pressure without breakage

c. Resist external pressure without breakage

d. Twist or bend without breakage

e. Resist heating without breakage

24. The lowest point of the inside of a pipe is known as the

a Pervert

b. Sofﬁt

*c.Invert

d. Curb stop

e. None of the above

25. A lightweight type of pipe that has a very smooth interior, is essentially corrosion-free, and

which is difﬁcult to locate when buried is

*a. Polyvinyl chloride

b. Cast iron

c. Ductile iron

d. Concrete cylinder

e. Steel

346

Chapter 11. Assessments Solutions

11.8 Chapter 9 - Safety

1. What federal law is designed to protect the safety and health of operators?

*a. OSHA

b. FMLA

c. FLSA

d. ADEA

2. What are the two most important safety concerns when entering a conﬁned space?

a. Corrosive chemicals and falls

b. Bad odors and claustrophobia

c. Extreme air temperatures and slippery surfaces

*d. Oxygen deﬁciency and hazardous gases

3. Which document provides a proﬁle of hazardous substances?

a. CERCLA

b. SARA

c. CFR

*d. SDS

4. What is the purpose of a pump guard?

a. Allows operators to turn off pump in emergency situations

b. Notiﬁes operators of excessive temperatures

c. Allows operators to pump against a closed discharge valve

*d. Protects operators from rotating parts

5. Atmosphere is considered oxygen deﬁcient when the oxygen level is below

a. 21.5%

b. 20%

*c. 19.5%

d. 17%

6. Employee hazards include

a. Noxious or toxic gases or vapors

b. Oxygen deﬁciency

c. Physical injuries

*d. All of the above

7. Before entering a permit-required conﬁned space, you must:

a. Check the atmosphere with a calibrated gas detector.

b. Make notiﬁcation that personnel are entering the space.

c. Lock out and tag out all equipment.

*d. All of the above.

8. When making a sulfuric acid dilution, the appropriate method is:

a. Add the water to the acid.

*b. Add the acid to the water.

11.8 Chapter 9 - Safety

347

c. Add both at the same time.

d. None of the above.

9. When manually lifting any object, be sure to

a. Hold it at arm’s length.

b. Keep your back bent and hold it low.

*c. Keep it close to your body and use leg strength.

d. Keep your knees locked and bend at the waist.

10. What is the proper slope of a ladder?

*a. Every 4 feet up the ladder is 1 foot out from the wall.

b. Every 5 feet up the ladder is 1 foot out from the wall.

c. Every 6 feet up the ladder is 1 foot out from the wall.

d. Every 7 feet up the ladder is 1 foot out from the wall.

11. When working on a chemical feed pump, what of the following is not required?

a. Nitrile gloves.

b. Safety glasses.

*c. Leather work gloves.

d. Full face shield.

12. When must the atmosphere of a conﬁned space be tested?

a. Only before a worker enters

b. Never, if adequate ventilation exists

*c. Continuously

d. Only if welding or painting is being performed

13. Some gases in a conﬁned space can be:

a. Colorless

b. Odorless

c. Deadly

*d. All of the above

14. Why should you contact other area companies with underground utilities before starting an

underground repair job?

a. To determine if there have been recent excavations in that location

*b. To ask these companies to mark the location of their utilities in the area of the repair

job

c. To see if they also have excavating to do in the area

d. To see if they will help route trafﬁc while you are doing the repair job

15. The only acceptable breathing device to wear while handling chlorine leaks is the

a. Activated carbon canister type

b. Potassium tetroxide canister type

*c. Self-contained breathing apparatus

d. Oxygen supply apparatus

348

Chapter 11. Assessments Solutions

11.9 Chapter 10 - Math

Practice Problems - Fractions

1. Convert 22 into a fraction

Solution:

22∗4+1

2. Express 10ft 6in as a fraction

Solution:

10∗2+1

6” = 6in∗

ft or 0.5ft =⇒ 10 ft6in = 10 ft =

12 in 12

105 5∗21

5∗2

Alternatively : 10 ft 6” is 10ft + 0.5 ft = 10.5 ft =⇒ 10.5 =

3. Express 10ft, 6in as decimal

Solution:

10 ft 6” is 10+0.5 = 10.5 ft

4. Add

3 1

4 7

For the two fraction

Lowest common denominator would be 4*7=28

Write each of the fractions as a fraction with a denominator of 28 by multiplying with a

fraction which equals to 1

28 28

∗

As both fractions have a common denominator, the numerators can now be added

28 28

21+4

5. Multiply

Solution:

∗

¡ꢂ ¡ꢂ

∗

=⇒

∗

¡ꢂ

ꢁ>

ꢁ

Practice Problems - Decimals and Powers of Ten

1. Write the equivalent of 10,000,000 as a power of ten

Solution:

10⁷

2. Find the product of 3.4564∗10²

Solution:

345.64

3. Find the product of 534.567∗10⁻²

Solution:

5.34567

11.9 Chapter 10 - Math

349

165.93

10⁻²

4. Find the value of

Solution:

1.6593

5. Find the value of 0.023∗10⁴

Solution:

230

Practice Problems - Rounding and Signiﬁcant Digits

Round the following to the nearest hundredths (the second place after the decimal).

A. 2.4568

B. 27.2534

C. 128.2111

D. 364.8762

E. 354.777777

F. 34.666666

G. 67.33333

Solution:

A. 2.46

B. 27.25

C. 128.21

D. 364.88

E. 354.78

F. 34.67

G. 67.33

Round the following to the nearest tenths (the ﬁrst place after the decimal).

A. 2.4568

B. 27.2534

C. 128.2111

D. 364.8762

E. 354.777777

F. 34.666666

G. 67.33333

Solution:

A. 2.5

B. 27.3

C. 128.2

350

Chapter 11. Assessments Solutions

D. 364.9

E. 354.8

F. 34.7

G. 67.3

Round the following answers off to the most signiﬁcant digit.

Problem

Accurate Answer

51.5

A. 25.1+26.43

B. 128.456−121.4 7.1

C. 85−7.92432

D. 8.564+5

Problem

Accurate Answer

A. 26.34×124.34567 3,275

B. 23.58×34.251

C. 12,453/13.9

D. 12,457.92×3

807.6

896

40,0000

Practice Problems - Totalizing and Averages

1. Find the average of the following set of numbers:

0.2

0.1

0.3

0.2

0.4

0.6

0.1

0.3

Solution:

0.2+0.2+0.1+0.3. +0.2+0.4+0.6+0.1+0.3

= 2.67

2. The chemical used for each day during a week is given below. Based on these data, what

was the average lb/day chemical used during the week?

11.9 Chapter 10 - Math

351

Monday

Tuesday

92 lb/day

93 lb/day

Wednesday 98 lb/day

Thursday

Friday

93 lb/day

89 lb/day

93 lb/day

97 lb/day

Saturday

Sunday

Solution:

92+93+98+93+89+93+97

= 93.6

3. The average chemical use at a plant is 77 lb/day. If the chemical inventory is 2800 lbs, how

many days supply is this?

Solution:

day

77 lb

2800 ¨lbs∗

= 36 days

4. A well pumped for 45 days. The beginning gallon meter reading was 7,456,400 and 45

days later the same meter was 15,154,400. What was the average ﬂow in gallons per day?

Solution:

Total Flow

Number of days

15,154,400−7,456,400

Average ﬂow =

= 171,067 gallons

Practice Problems - Percentage

1. 25% of the chlorine in a 30-gallon vat has been used. How many gallons are remaining in

the vat?

Solution:

Amount of chlorine remaining in the vat is 100%-25%=75%

Gallons of chlorine remaining in the vat: 30∗0.75 = 22.5 gallons

2. The annual public works budget is $147,450. If 75% of the budget should be spent by the

end of September, how many dollars are to be spent? How many dollars will be remain-

ing?

Solution:

Amount to be spent = $147,450*0.75 = $110,812.50

Amount remaining = $ 147,450 - 110,812.50 = $36,367.50

3. A 75 pound container of calcium hypochlorite has a purity of 67%. What is the actual

weight of the calcium hypochlorite in the container?

Solution:

Note: Calcium Hypochlorite can be written as Ca(OCl)₂

(

0.67 lbs Ca(OCl)₂

(

75 lbs Ca(OCl)₂− product in container∗

(

lb Ca(OCl)₂− product in container

(

352

Chapter 11. Assessments Solutions

50.25 lbs Ca(OCl)₂

4. 3/4 is the same as what percentage?

Solution:

∗100 = 75%

5. A water plant produces 84,000 gallons per day. 7,560 gallons are used to backwash the

ﬁlter. What percentage of water is used to backwash?

Solution:

7560

84000

∗100 = 9%

6. The average day winter demand of a community is 14,500 gallons. If the summer demand

is estimated to be 72% greater than the winter, what is the estimated summer demand?

Demand - When related to use, the amount of water used in a period of time. The term is

in reference to the "demand" put onto the system to meet the need of customers.

Solution:

(1+0.72)∗14,500 = 24,940gallons

7. The master meter for a system shows a monthly total of 700,000 gallons. Of the total wa-

ter, 600,000 gallons were used for billing. Another 30,000 gallons were used for ﬂushing.

On top of that, 15,000 gallons were used in a ﬁre episode and an estimated 20,000 gallons

were lost to a main break that was repaired that same day. What is the total unaccounted

for water loss percentage for the month?

Solution:

600000+30000+150000+20000

1−

∗100 = 5%

700000

8. Your water system takes 75 coliform tests per month. This month there were 6 positive

samples. What is the percentage of samples which tested positive? Solution:

∗100 = 8%

Practice Problems - Ratio and Proportion

1. It takes 6 gallons of chlorine solution to obtain a proper residual when the ﬂow is 45,000

gpd. How many gallons will it take when the ﬂow is 62,000 gpd?

Solution:

Required gallons of chlorine is directly proportional to the ﬂow being treated.

6 gallons

45,000 gpd 62,000 gpd

X gallons

Thus,

Solving for X:

6∗62,000

=⇒ X =

= 8.3 lbs bleach

45,000

11.9 Chapter 10 - Math

353

2. A motor is rated at 41 amps average draw per leg at 30Hp. What is the actual Hp when the

draw is 36 amps? C. Solution:

Ampere draw and horsepower (Hp) are directly proportional - when Hp goes up, the am-

pere draw goes up

30 Hp

41 Amperes 36 amperes

X Hp

Thus,

Solving for X:

6∗62,000

=⇒ X =

= 8.3 lbs bleach

45,000

3. If it takes 2 operators 4.5 days to clean an aeration basin, how long will it take three opera-

tors to do the same job? Solution:

Number of operators and the time required to accomplish a certain task are inversely pro-

portional - when more operators are involved, the task will take less time.

(2 Operators∗4.5 days) = (3 Operators∗X days) Solving for X:

2∗4.5

=⇒ X =

= 3 days

4. It takes 3 hours to clean 400 feet of collection system using a sewer ball. How long will it

take to clean 250 feet? Solution:

The hours to clean and length of system are directly proportional - when length goes up,

the hours go up and vice versa

3 hours

400 feet

X hrs

250 feet

Thus,

Solving for X:

3∗250

=⇒ X =

= 1.9 lbs hours

400

5. It takes 14 cups of HTH to make a 12% solution, and each cup holds 300 grams. How

many cups will it take to make a 5% solution?

Solution:

The number of HTH cups/grams and percent solution are directly proportional - more

cups/grams are required for a higher percent solution.

14 cups

12% solution 5% feet

X hrs

Thus,

Solving for X:

14∗5

=⇒ X =

= 5.83 cups

6. A bike travelling at 5 miles/hr completes a journey in 40 minutes. How long would the

same journey take if the speed was increased to 8 miles/hr?

Solution:

The bike speed and the time to complete a journey are inversely proportional - more speed

then less time to complete a journey.

354

Chapter 11. Assessments Solutions

(5 mph∗40 minutes) = (8 mph∗X min) Solving for X:

5∗40

=⇒ X =

= 25 min

7. Water is ﬂowing at a velocity of 1.3ft/sec in a 4.0-in. diameter pipe. If the pipe changes

from the 4.0-inch to a 3.0-in. pipe, what will the velocity be in the 3.0-in. pipe?

Solution:

This problem is solved here using proportional relationship. Note: This is a simpler way

of solving compared to the method used to solve the same problem in the Flow - Velocity

section.

• Q (Flow) = V (Velocity) * A (Area) =⇒ V =

•

As the ﬂow is the same in both - 4 in and 3 in pipes - Q is a constant, V and A are

inversely proportional.

• Therefore, V₁*A₁=V₂*A₂

• As A= ∗D²

• As is a constant, V₁*D₁²=V₂*D₂²or V_4in*D₄in ²=V₃in*D₃in ².

(1.3∗4²) = (X ∗3²)

Solving for X:

1.3∗4²

=⇒ X =

= 2.3 ft/s

3²

Practice Problems - Area and Volume

1. A 60-foot diameter tank contains 422,000 gallons of water. Calculate the height of water in

the storage tank.

ꢃ

Volume− ft

Volume = Area * Height =⇒ Height(ft) =

Area ft²

Volume (ft³) = ∗D²∗ fillheight = 0.785∗17.5²ft²∗14ft = 240 ft³

2. What is the volume of water in ft³, of a sedimentation basin that is 22 feet long, and 15 feet

wide, and ﬁlled to 10 feet?

Volume = Length * Width * Height = 22 ft * 15 ft * 10 ft = 3300 ft³

Volume (ft³) = ∗D²∗ fill height = 0.785∗17.5²ft²∗14 ft = 240 ft³

3. What is the volume in ft³of an elevated clear well that is 17.5 feet in diameter, and ﬁlled to

14 feet?

Volume = Area * Height

Volume (ft³) = ∗D²∗ fillheight = 0.785∗17.5²ft²∗14ft = 240 ft³

4. What is the area of the top of a storage tank that is 75 feet in diameter?

Area (ft²) = ∗D²= 0.785∗75²ft²= 0.785 = 4416 ft²

11.9 Chapter 10 - Math

355

5. What is the area of a wall 175ft. in length and 20ft. wide?

Solution:

Area = 175∗20 = 3,500ft²

6. You are tasked with ﬁlling an area with rock near some of your equipment. 1 Bag of rock

covers 250 square feet. The area that needs rock cover is 400 feet in length and 30 feet

wide. How many bags do you need to purchase?

Solution:

Bag

250 ft²

Area to be covered = 400’ * 30’ = 12,000 ft²=⇒ 12,000 ft²

∗

= 48 bags

7. How many gallons of paint will be required to paint the walls of a 40 ft long x 65 ft wide

x 20 ft high tank if the paint coverage is 150 sq. ft per gallon. Note: We are painting walls

only. Disregard the ﬂoor and roof areas.

Solution:

Ceiling

Wall - L*H

Wall - W*H

Height=20’

Wall - W*H

Wall - L*H

Floor

Length=45’

Width=65’

2 Walls W*H + 2 Walls L*H = 2∗65∗20ft²+2∗45∗20ft²= 2,600+1,800 = 4,400ft²

ft²

gal

4,400ft²

=⇒ @150

paint coverage →

= 30 gallons

ft²

150

gal

8. A new 24" diameter pipe is to be installed with a pipe depth, to top of pipe, of 48" and

a length of 12,000 feet The trench will be backﬁlled with sand. The trench walls will be

excavated one foot wider than the pipe on each side and six inches below the pipe. How

much excavated material must be hauled away?

Solution:

48" cover

1200 ft length

1’

24" pipe diameter

6" from bottom

1’

Total volume to be excavated = Trench Length*Depth*Width

! !

48 24

12 12 12

cu.yds

27ft³

1200ft ∗

ft ∗ 1+ +1 ft

∗

= 1156cu.yds

9. A chemical feed pump with a 6-inch bore and a 6-inch stroke pumps 60 cycles per minute.

Find the pumping rate in gpm.

356

Chapter 11. Assessments Solutions

Solution:

Total volume pumped = Volume per stroke * cycles per minute

ꢀ

ft³

60 cycles 7.48 gal

ꢀ

=⇒ 0.785∗

∗

= 44 gpm

ft³

min

cycle

Practice Problems - Flow and Velocity

1. Flow in an 8-inch pipe is 500 gpm. What is the average velocity in ft/sec? (Assume pipe is

ﬂowing full)

Solution:

Flow (Q) = Velocity (V)×Area (A) =⇒ Q = V ∗A =⇒ V =

We need to convert Q which is given in gpm to ft³/sec and calculate the area of the pipe in

ft²so velocity can be valculated in ft/sec.

ꢃ

sec

A ft

Step 1 - Converting Q - 500 gpm to ft³/min:

ꢀ

500 gallons

ft³

min

ft³

sec

ꢀ

∗

= 1.1

ꢀ

min

7.48 gallon 60 sec

ꢀ

Step 2 - Calculating area in ft²:

ꢂ

ꢃ

144

Area ft²= ∗D²= 0.785∗

ft²= 0.785∗

= 0.349 ft²

1.1 ft³/sec

0.349 ft²

=⇒ V

= 3.2 ft/sec

sec

2. A pipeline is 18” in diameter and ﬂowing at a velocity of 125 ft. per minute. What is the

ﬂow in gallons per minute?

Solution:

Flow (Q) = Velocity (V)×Area (A)

As the velocity is given in ft/min, and the area can be calculated in ft², ﬂow can be calu-

lated in ft³/min and then converted to gal/min.

Step 1: Calculating area in ft²:

ꢂ

ꢃ

324

144

Area (ft²) = ∗D²= 0.785∗

ft²= 0.785∗

= 0.349 ft²

Step 2: Calculate ﬂow in ft³/min:

min

ft³

min

Q ft³/min = 125

∗1.77 ft²= 221.25

11.9 Chapter 10 - Math

357

Step 3: Convert Q to gallons per minute

ft³

min

gal

ft³

gal

min

Q = 221.25

∗7.48

= 1655

3. The velocity in a pipeline is 2 ft./sec. and the ﬂow is 3,000 gpm. What is the diameter of

the pipe in inches?

Solution:

Flow (Q) = Velocity (V)×Area (A) =⇒ Q = V ∗A =⇒ A =

We need to convert Q which is given in gpm to ft³/sec and calculate the area of the pipe in

ft²given the velocity.

From the calculated area of the pipe, the pipe diameter can be calculated.

ft²

ꢃ

sec

ꢃ

sec

Step 1 - Converting Q - 3000 gpm to ft³/sec:

ꢀ

3000 gallons

ft³

min

ft³

sec

ꢀ

∗

= 6.68

ꢀ

min

7.48 gallon 60 sec

ꢀ

Step 2 - Calculating area in ft²:

6.68ft³/sec

=⇒ A ft²=

= 3.34ft²

sec

ꢂ

ꢃ

0.785

Area (A) = ∗D²= 0.785∗D²=⇒ D²=

=⇒ D =

ꢂ

ꢃ

3.34

0.785

=⇒ D =

= 2 ft

4. Find the ﬂow in a 4-inch pipe when the velocity is 1.5 feet per second.

Solution:

Flow (Q) = Velocity (V)×Area (A)

The velocity is given in ft/sec and after calculating the area in ft², ﬂow can be calculated in

ft³/min.

Step 1: Calculating area in ft²:

ꢂ

ꢃ

324

144

Area (ft²) = ∗D²= 0.785∗

ft²= 0.785∗

= 0.087 ft²

Step 2: Calculate ﬂow in ft³/min:

sec

ft³

sec

Q ft³/min = 1.5

∗0.087 ft²= 0.13

358

Chapter 11. Assessments Solutions

Q can be converted to a more commonly used gallons per minute unit

ft³

sec

gal

ft³

sec

min

gal

min

Q = 0.13

∗7.48

∗60

= 59

5. A 42-inch diameter pipe transfers 35 cubic feet of water per second. Find the velocity in

ft/sec.

Solution:

Flow (Q) = Velocity (V)×Area (A) =⇒ Q = V ∗A =⇒ V =

Q is already given in ft³/sec. We need to ﬁrst calculate the area of the pipe in ft²so veloc-

ity can be valculated in ft/sec.

ꢃ

sec

A ft²

Step 1 - Calculating area in ft²:

ꢂ

ꢃ

1764

144

Area ft²= ∗D²= 0.785∗

ft²= 0.785∗

= 9.616 ft²

35 ft³/sec

=⇒ V

= 3.6ft/sec

sec 9.616 ft²

6. A plastic ﬂoat is dropped into a channel and is found to travel 10 feet in 4.2 seconds. The

channel is 2.4 feet wide and the water is ﬂowing 1.8 feet deep. Calculate the ﬂow rate of

water in cfs.

Solution:

Q = V ∗A =⇒ V =

Flow (Q) = Velocity (V)×Area (A)

10 ft

The speed of the ﬂoat travelling is the velocity of the water =⇒ Velocity =

4.2 sec

10 ft

4.2 sec

ft³

sec

Thus ﬂow =

∗(2.4∗1.8)ft²= 4.32

7. A channel is 3.25 feet wide and is conveying a a ﬂow of 3.5 MGD. The depth of the water

is 8 inches. Calculate the velocity of this ﬂow.

Solution:

11.9 Chapter 10 - Math

359

Q = V ∗A =⇒ V =

day

ꢁ

MG 1000000gal

ꢁ

3.5

∗

ꢁ

day

7.48gal (1440∗60)s

ꢁ

=⇒ V

= 2.2

(3.25∗0.75)ft²

Practice Problems - Unit Conversions

1. Convert 1000 ft³to cu. yards

Solution:

yd³

27 ft³

yds³= 1000ft³∗

= 37 yds³

2. Convert 10 gallons/min to ft³/hr

Solution:

ft³

gal

ft³

60min

ft³

ꢁ

= 10

∗

= 80.2

ꢁ

min 7.48gal

ꢁ

3. Find the ﬂow in gpm when the ﬂow is 0.25cfs.

Solution:

gal

min

ft³7.48gal 60sec

gal

min

= 0.25

∗

= 112.2

vspace0.2cm

ft³

sec

min

4. The ﬂow rate through a ﬁlter is 4.25 MGD. What is this ﬂow rate expressed as gpm?

Solution:

day

gal

min

MG 1,000,000gal

gal

min

= 4.25

∗

= 2,951

day

1,440min

5. After calibrating a chemical feed pump, you’ve determined that the maximum feed rate is

178 mL/ minute. If this pump ran continuously, how many gallons will it pump in a full

day?

Solution:

gal

day

1,440min

gal

day

= 178

∗

= 119,680

min 1000mL

day

6. A plant produces 2,000 cubic foot of water per hour. How many gallons of water is pro-

duced in an 8-hour shift?

Solution:

ꢁ

gal

8−hr shift

ft³7.48gal

8hr

gal

day

ꢁ

= 2,000

∗

= 253.6

ft³

ꢁ

8−hr shi ft

ꢁ

7. Change 70 °F to °C

360

Chapter 11. Assessments Solutions

Solution:

^◦F −32 70−32

^◦C =

= 21.1^◦C

1.8

8. Change 4 °C to °F

Solution:

^◦F = (^◦C ×1.8)+32 = (4∗1.8)+32 = 39.2^◦F

Practice Problems - Concentration

1. How many lbs of salt needs to be dissolved in water to make 1 liter of 5% salt solution?

Solution:

5% salt solution =⇒ 50,000 mg/l salt

To prepare 1 litre of salt solution need to dissolve 50,000 mg or:

50,000 mg∗

solution.

∗

= 0.11 lb salt in enough water to make 1 liter of

453.6 gms 1,000 mg

2. What is the concentration in mg/l of 4.5% solution of that substance.

450,000mg/l

3. An operator mixes 40 lb of lime in a 100-gal tank containing 80 gal of water. What is the

percent of lime in the slurry? Solution:

40 lbs lime

1,000,000 lbs

million lbs

∗

ppm∗

lbs

10,000 ppm

80 gal water ∗8.34

+40 lbs lime

gal water

5.7%

Practice Problems - Density and Speciﬁc Gravity

1. What is the speciﬁc gravity of a 1 ft³concrete block which weighs 145 lbs? Solution:

Speciﬁc gravity is the ratio of the weight of the substance to that of an equal volume of

water.

As one cu. ft of water weighs 62.43 lbs/cu. ft (8.34 lbs/gal*7.48 gal/cu. ft):

145

Speciﬁc gracvity of this concrete block=

= 2.3

62.43

2. What is the speciﬁc gravity of a chlorine solution if 1 (one) gallon weighs 10.2lbs? Solu-

tion:

Speciﬁc gravity is the ratio of the weight of the substance to that of an equal volume of

water.

10.2

8.34

As one gallon of water weighs 8.34 lbs: Speciﬁc gracvity of this chlorine solution=

1.2

11.9 Chapter 10 - Math

361

3. How much does each gallon of zinc orthophosphate weigh (pounds) if it has a speciﬁc

gravity of 1.46?

Solution:

gal

8.34

∗1.46 = 12.18

4. How much does a 55 gallon drum of 25% caustic soda weigh (pounds) if the speciﬁc

gravity is 1.28?

Solution:

gal

ꢁ

8.34

∗1.28∗55gal = 12.18

ꢁ

gal

ꢁ

Practice Problems - Pounds Formula

1. A water treatment plant operates at the rate of 75 gallons per minute. They dose soda ash

at 14 mg/L. How many pounds of soda ash will they use in a day?

lbs/day

14 mg/l

75 GPM

8.34

lbs

day

= Flow

∗Concentration

∗8.34

ꢀ

lbs

day

gallons

min

lbs

ꢀ

= 75

∗1440

∗

∗250

∗8.34 = 225

day

ꢀ

min

day 1,000,000 gallons

ꢀ

2. What is the inﬂuent plant loading of phosphorus in lbs/day if the plant ﬂow is 4.5 MGD

and the inﬂuent phosphorous concentration is 1.5 mg/l?

Solution:

? lbs/day

1.5 mg/l

4.5 MGD

8.34

362

Chapter 11. Assessments Solutions

1.5

∗4.5MGD∗8.34 = 56 lbs/day

3. A water treatment plant uses 8 pounds of chlorine daily and the dose is 17 mg/l. How

many gallons are they producing? Solution:

8 lbs/day

17 mg/l

MGD

8.34

lbs

day

= Flow

∗Concentration

∗8.34

lbs

day

lbs

day

=⇒ Flow

= 0.056425

Concentration

∗8.34 17

∗8.34

MG 1,000,000 Gallons

0.056425

∗

= 56,425 Gallons

day

Practice Problems - Chemical Dosing

1. In order to disinfect a sedimentation basin measuring 20ft in width, 60 feet in length, and

is 10 feet deep to obtain 50ppm would require how many lbs. of 65% available HTH ?

a) 5.0lbs

b) 41.3lbs

c) 37.4lbs

*d) 57.6lbs

2. Determine the chlorinator setting (lb/day) required to treat a ﬂow of 4MGD with a chlorine

dose of 5mg/L.

Chlorine feed rate (lb/ day ) = Chlorine (mg/L)× Flow (MGD)×8.34lb/gal

Chlorine feed rate (lb/ day ) = 5mg/L×4MGD×8.34lb/gal

Chlorine feed rate (lb/ day ) = 167lb/ day

3. A pipeline that is 12 inches in diameter and 1400ft long is to be treated with a chlorine

dose of 48mg/L. How many lb of chlorine will this require?

First determine the gallon volume of the pipeline:

Volume (gal) = 0.785×D²× length (ft)×7.48gal/cuft

Volume (gal) = 0.785×(1ft)²×1400ft×7.48gal/cuft Volume (gal) = 8221gal

Next calculate the amount of chlorine required:

Chlorine feed rate (lb/ day ) = Chlorine (mg/L) x Flow ( MGD) ×8.34lb/gal

11.9 Chapter 10 - Math

363

Chlorine feed rate (lb/ day ) = 48mg/L×0.008221MGD×8.34lb/gal

Chlorine feed rate (lb/ day ) = 3.3lb

4. What should the chlorinator seting be (lb/day) to treat a ﬂow of 2.35MGD if the chlorine

demand is 3.2mg/L and a chlorine residual of 0.9mg/L is desired?

First, determine the chlorine dosage (in mg/L ):

Chlorine Dose (mg/L) = Chlorine Demand + Chlorine Residual

Chlorine Dose (mg/L) = 3.2mg/L+0.9mg/L

Chlorine Dose (mg/L) = 4.1mg/L

Next calculate the chlorine dosage (feed rate) in lb/ day:

Chlorine feed rate (lb/ day ) = Chlorine (mg/L)× Flow (MGD)×8.34lb/gal

Chlorine feed rate (lb/ day ) = 4.1mg/L×2.35MGD×8.34lb/gal

Chlorine feed rate (lb/ day ) = 80.4lb/ day

5. A water treatment plant operates at the rate of 75 gallons per minute. They dose soda ash

at 14 mg/L. How many pounds of soda ash will they use in a day? Solution:

lbs/day

14 mg/l

75 GPM

8.34

lbs

day

= Flow

∗Concentration

∗8.34

ꢀ

lbs

day

gallons

min

lbs

ꢀ

= 75

∗1440

∗

∗14

∗8.34 = 12.6

day

ꢀ

min

day 1,000,000 gallons

ꢀ

6. A water treatment plant is producing 1.5 million gallons per day of potable water, and uses

38 pounds of soda ash for pH adjustment. What is the dose of soda ash at that plant?

Solution:

38 lbs/day

mg/l

1.5 MGD

8.34

364

Chapter 11. Assessments Solutions

lbs

day

= Flow

∗ Concentration

∗ 8.34 =⇒ Concentration

Flow

∗8.34

lbs

day

Concentration

= 3

1.5

∗8.34

7. A water treatment plant produces 150,000 gallons of water every day. It uses an average

of 2 pounds of permanganate for iron and manganese removal. What is the dose of the

permanganate?

Solution:

38 lbs/day

mg/l

1.5 MGD

8.34

lbs

day

= Flow

∗ Concentration

∗ 8.34 =⇒ Concentration

Flow

∗8.34

lbs

day

Concentration

= 3

ꢀ

Gallons

ꢀ

150,000

∗

∗8.34

(

day

1,000,000 Gallons

8. A water treatment plant uses 8 pounds of chlorine daily and the dose is 17 mg/l. How

many gallons are they producing?

Solution:

8 lbs/day

17 mg/l

MGD

8.34

lbs

day

= Flow

∗Concentration

∗8.34

11.9 Chapter 10 - Math

365

lbs

day

lbs

day

=⇒ Flow

= 0.056425

Concentration

∗8.34 17

∗8.34

MG 1,000,000 Gallons

0.056425

∗

= 56,425 Gallons

day

Practice Problems - Blending and Dilution

1. Ferric chloride is being added as a coagulant to the raw water entering a plant. Sampling

shows that the concentration of ferric in the raw water is 25 ppm. A quick check of the

chemical metering pump shows that it is operating at a ﬂow rate of 4.3 gpm. If the ﬂow

through the water plant is 800 gpm, what is the concentration of raw chemical in the dos-

ing tank?

Solution:

FeCl₃

V_FeCl=4.3gpm

C_FeCl= ?

Water

800gpm

C₂=25ppm FeCl₃

V₂=4.3+800=804.3 gpm

C₁* V₁= C₂* V₂

C_FeCl* V_FeCl= C₂* (V_FeCl+V_Water

)

C_FeCl* 4.3 = 25 * (804.3)

25∗(804.3)

= 4,676 ppm or 0.47%

C_FeCl

4.3

2. A water plant is fed by two different wells. The ﬁrst well produces water at a rate of 600

gpm and contains arsenic at 0.5 mg/L. The second well produces water at a rate of 350

gpm and contains arsenic at 12.5 mg/L. What is the arsenic concentration of the blended

water?

Solution:

C₁* V₁+ C₂* V₂+ = C₃* V₃=C₃*(V₁+ V₂)

C_{Well 1}* V_{Well 1}+ C_{Well 2}* V_{Well 2}= C_Blend* V_Blend=C_Blend*(V_{Well 1}+ V_Well

)

C_{Well 1}∗V_{Well 1}+C_{Well 2}∗V_Well

0.5∗600+12.5∗350

600+350

=⇒ C_Blend

= 4.9 mg/l

V_{Well 1}+V_Well

Practice Problems - Pumping Rates

1. How long will it take (hrs) to ﬁll a 2 ac-ft pond if the pumping rate is 400 GPM?

366

Chapter 11. Assessments Solutions

ꢀ

325,851 gallons

ꢀ

2 Ac− ft ∗

ꢀ

Volume

Flow

ꢀ

Ac− ft

ꢀ

Time to fill (hours) =

= 27 hours

ꢀ

gallons 60 min

ꢀ

400

∗

min

2. A pump is set to pump 5 minutes each hour. It pumps at the rate of 35 gpm. How many

gallons of water are pumped each day?

Solution:

ꢁ

35 gal sludge 5 min 24 hr

4,200 gallons

ꢁ

∗

ꢁ

min

day

ꢁ

3. A pump operates 5 minutes each 15 minute interval. If the pump capacity is 60 gpm, how

many gallons are pumped daily?

H¨

60 gal sludge 5 min

min

28,800 gal sludge

¨H

∗

∗1440

H¨

min

¨H

15 min

day

4. Given the tank is 10ft wide, 12 ft long and 18 ft deep tank including 2 ft of freeboard when

ﬁlled to capacity. How much time (minutes) will be required to pump down this tank to a

depth of 2 ft when the tank is at maximum capacity using a 600 GPM pump

Solution:

2’ Freeboard

16’ Water Depth (Initial)

2’ Water Depth (Final)

10’ Wide

12’ Long

Volume to be pumped=12 ft ∗10 ft ∗(16−2) ft = 1,680ft³

ꢁ

gal

1,680ft³∗7.48

ꢁ

ft³

=⇒

= 21min

ꢁ

gal

ꢁ

600

min

Practice Problems - Pressure, Force and Head Relationship

1. A 42-inch main line has a shut off valve. The same line has a 10-inch bypass line with

another shut-off valve. Find the amount of force on each valve if the water pressure in the

line is 80 psi. Express your answer in tons.

Solution:

Force = Pressure×Area

lbs

in²

1ton

2000lbs

Force on the 42-in valve: =⇒ 80

∗0.785∗(42in)²∗

= 3.39 tons

11.9 Chapter 10 - Math

367

lbs

in²

1ton

2000lbs

Force on the 10-in valve: =⇒ 80

∗0.785∗(10in)²∗

= 3.39 tons

2. A water tank is 15 feet deep and 30 feet in diameter. What is the force exerted on a 6-inch

valve at the bottom of the tank?

Force = Pressure×Area

0.433 psi

=⇒ 15 ft∗

∗0.785∗(6in)²= 183 lbs

3. A water tank is ﬁlled to depth of 22 feet. What is the psi at the bottom of the tank?

Solution:

0.433psi

22 ft ∗

= 9.5 psi

ꢀ

ft head

ꢀ

4. The static pressure in a water main is 85 psi. What elevation of water is needed to provide

that kind of pressure?

Solution:

ft head

ꢁ

85 psi∗

= 196.3 feet

ꢁ

0.433psi

ꢁ

5. The pressure at the top of the hill is 62 psi. The pressure at the bottom of the hill, 60 feet

below, is 100 psi. The water is ﬂowing uphill at 120 gpm. What is the friction loss, in feet,

in the pipe?

Pressure = 62psi

60’

Flow = 120gpm

Pressure = 100psi

Total headloss = Headloss due to elevation gain + Headloss due to friction

=⇒ Headloss due to friction = Total headloss - Headloss due to elevation gain

ft head

ꢁ

Total headloss = (100−62) psi∗

= 87.8 ft

ꢁ

0.433psi

ꢁ

Headloss due to elevation gain = 60 ft

=⇒ Headloss due to friction = 87.8−60 = 27.8 ft

Practice Problems - Pumping Power Requirements

1. If a pump is operating at 2,200 gpm and 60 feet of head, what is the water horsepower? If

the pump efﬁciency is 71%, what is the brake horsepower?

Solution:

water Hp = ﬂow * head

2,200GPM ∗60ft ∗

= Water Hp = 33.3Hp

3,960GPM − ft

368

Chapter 11. Assessments Solutions

pump Hp = brake Hp * pump efﬁciency

33.3

0.71

brake Hp =

= Brake Hp = 47Hp

2. The water horsepower of a pump is 10Hp and the brake horsepower output of the motor is

15.4Hp. What is the efﬁciency of the pump?

Solution:

10BHp

15.4EHp

η_p=

×100 = 65%

3. The water horsepower of a pump is 25Hp and the brake horsepower output of the motor is

48Hp. What is the efﬁciency of the pump?

Solution:

25 Water Hp

48 brake Hp

η_p=

×100 = 52%

4. The efﬁciency of a well pump is determined to be 75%. The efﬁciency of the motor is

estimated at 94%. What is the efﬁciency of the well?

Solution:

Well e f ficiency = η_m∗η_p=⇒ 0.94×0.75 = 0.705×100 = 71%

5. If a motor is 85% efﬁcient and the output of the motor is determined to be 10 BHp, what is

the electrical horsepower requirement of the motor? Solution:

10BHp

= 11.8EHp or Input Hp

0.85

6. The water horsepower of a well with a submersible pump has been calculated at 8.2 WHp.

The Output of the electric motor is measured as 10.3BHp. What is the efﬁciency of the

11.9 Chapter 10 - Math

369

pump?

Solution:

82 W Hp

10.3 BHp

η_p=

×100 = 79.6%

7. Water is being pumped from a reservoir to a storage tank on a hill. The elevation difference

between water levels is 1200 feet. Find the pump size (in Hp) required to ﬁll the tank at a

rate of 120 gpm.

Water

Storage

Flow = 120gpm

Elevation difference = 1200 ft

Solution:

water Hp = ﬂow * head

3,960GPM − ft

120GPM ∗1,200ft ∗

= Water Hp = 36.4Hp

Practice Problems - Well Hydraulics

1. A well yields 2,840 gallons in exactly 20 minutes. What is the well yield in gpm?

Solution:

2,840gal

20min

gal

min

= 142

2. Before pumping, the water level in a well is 15 ft. down. During pumping, the water level

is 45 ft. down. The drawdown is:

Solution:

45−15 = 30ft

3. A well is located in an aquifer with a water table elevation 20 feet below the ground sur-

face. After operating for three hours, the water level in the well stabilizes at 50 feet below

370

Chapter 11. Assessments Solutions

the ground surface. Calculate the pumping water level.

Solution:

50 ft

4. Calculate drawdown, in feet, using the following data:

The water level in a well is 20 feet below the ground surface when the pump is not in

operation, and the water level is 35 feet below the ground surface when the pump is in

operation.

Solution:

Drawdown = 35ft−20ft = 15 ft

5. Calculate the well yield in gpm, given a drawdown of 14.1 ft and a speciﬁc yield of 31

gpm/ft.

Solution:

Yield (gpm)

Specific Yield (gpm/ ft) =

Drawdown (ft)

=⇒ Yield (gpm) = Speci fic Yield (gpm/ ft)∗Drawdown (ft) = 31∗14.1 = 437.1 gpm

Practice Problems - Sedimentation

1. Calculate the detention time for a sedimentation tank that is 48 feet wide, 210 feet long

and 9 feet deep with a ﬂow of 5 MGD.

Solution:

Clari fier volume(cu. ft or gal)

Clari fier detention time (hr) =

Influent flow (cu. ft or gal)/hr)

(48∗210∗9)ft³

Clari fier detention time (hr) =

= 3.25hrs

ft³

day

ꢁ

5MG 10 gal

ꢁ

∗

7.48gal 24hrs

ꢁ

∗

day

ꢁ

2. At a 2.5 MGD wastewater treatment plant the primary clariﬁer has a detention time of 2

hours. How many gallons does this clariﬁer hold?

Solution:

Clari fier volume(gal)

Influent flow (gal/hr)

Clari fier detention time (hr) =

=⇒ Clari fier volume(gal) = Clari fier detention time (hr)∗Influent flow (gal/hr)

ꢂ

ꢃ ꢂ

ꢃ

gal

day

=⇒ Clari fier volume(gal) = 2 hrs ∗ 2.5∗10⁶

∗

= 208,333 gals

day 24 hrs

3. A circular clariﬁer has a diameter of 80 ft. If the ﬂow to the clariﬁer is 1800 gpm, what is

the surface overﬂow rate in gpm/ft?

Solution:

11.9 Chapter 10 - Math

371

= 0.36 gpm/ft²

Flow, gpm

1,800 gpm

Surface overﬂow rate =

Clariﬁer surface area, ft²(0.785∗80²)ft²

4. A sedimentation basin 70 ft by 25 ft receives a ﬂow of 1000 gpm. What is the surface

overﬂow rate in gpm/ft2?

Solution:

Flow, gpm

1,000 gpm

Surface overﬂow rate =

= 0.6 gpm/ft²

Clariﬁer surface area, ft²(70ft ∗25ft)ft²

5. A circular clariﬁer receives a ﬂow of 3.55 MGD. If the diameter of the weir is 90 ft, what

is the weir loading rate in gpm/ft?

Solution

Flow, gpm

Weir overﬂow rate =

Weir length ft

3.55 MG 1,000,000 gal

day

∗

1440 min

day

=⇒

= 2,465 gpm/ft

(3.14∗90) ft

Note: The concentration and volume (or ﬂow) units need to be the same. Thus, the gpm

ﬂow rate of Line 1 was converted to math the MGD ﬂow rate unit of Line 2.

Practice Problems - Filtration

1. At an average ﬂow of 4,000 gpm, how long of a ﬁlter run in hours would be required to

produce 25 MG of ﬁltered water?

Solution

Total flow (gal)

Flow rate (gpm) =

Filter run time (min)

Total flow (gal)

=⇒ Filter run time (min) =

Flow rate (gpm)

ꢁ

1,000,000 gal

min

ꢁ

=⇒ Filter run time (hr) = 25 MG∗

∗

∗60

min

= 104 hrs

ꢁ

4,000 gal

ꢁ

2. A ﬁlter is 40ft long by 20ft wide. During a test of ﬂow rate, the inﬂuent valve to the ﬁlter

is closed for 6 minutes. The water level drop during this period is 16 inches. What is the

ﬁltration rate for the ﬁlter in gpm/ft²?

Solution

12 in

gal

ft³

(40ft∗20ft∗16in∗

)ft³∗7.48

Filtration rate, gpm/ft²=

= 1.7 gpm/ ft²

40 ft ∗20 feet

3. A water treatment plant treats 6.0 MGD with four ﬁlters. Each ﬁlter use 60,000 gallons per

wash. What is the percent backwash at the plant?

Solution:

372

Chapter 11. Assessments Solutions

×100 = 4%

60,000∗4 gal

6,000,000 gal

Backwash water, % =

4. A treatment plant ﬁlter washes at a rate of 10,000 GPM. The ﬁlter measures 18ft. wide by

24ft. long. What is the rate of rise expressed in inches per minute?

Solution:

Backwash rate, gpm/ft²×12in/ft

Backwash rinse rate, in/min =

7.48gal/ft³

Based upon the above formula, the Backwash tate in gpm/ ft²needs to be calculated by

dividing the gpm ﬂow by the surface area

10,000gpm

18ft×24ft

12in

Backwash Rinse Rate, in/min =

= 37in/min

7.48gal/ft³

5. If a ﬁlter measures 20 feet by 30 feet by 7 foot deep and the backwash ﬂow is 3.5cuft/sec

what is the backwash rate?

Solution:

3.5 ft³7.48 gal 60 sec

∗

ft³

min

2.6 gpm

sec

Backwash Rate (gpm/sq.ft)=

(20∗30) ft²

Index

XII

Index

, 290

Biological contaminants, 62

Breakpoint Chlorination, 174

Conﬁned space, 266

Carbonate hardness or temporary hardness,

Advantages and Disadvantages of Surface

Water vs Groundwater , 48

Advantages of Chloramines, 173

Advantages of Chlorine Dioxide, 179

Advantages of ozonation, 180

Advantages of UV disinfection, 179

Aeration, 142

Categories of Treatment Methods, 128

Centrifugal pump

Maximum suction lift, 205

Centrifugal pump components

Backing plate, 200

Gland, 202

Aesthetic quality, 67

Lantern ring, 202

Air Valves, 232

Packing gland, 202

Packing/mechanical seals, 201

Shaft, 200

Alkalinity, 70

Annual water quality report, 111

Arsenic Rule, 108

Shaft sleeve, 201

Backﬂow Prevention, 235

Background, 127, 166

Stufﬁng box, 200

Volute case, 200

BATs for Inorganics, 148

BATs for Microbiological Contaminants,

150

Wear rings, 200

Centrifugal pumps

Frame mounted, 193

Impeller types, 193

Operating principle, 193

BATs for Radionuclides, 150

Best Available Technology (BAT), 148

376

INDEX

Split case, 194

Types, 193

Distribution Mains, 220

Distribution of earth’s water, 37, 38

Distribution System Map, 245

Distribution System Operation and

Maintenance Elements, 241

Chapter 2, 323

Chemical contaminants, 62

Chemical Feed Systems, 151

Chlorination Byproducts, 171

Chlorine Application, 171

Chlorine Dioxide, 178

Chlorine disinfection

Distribution System record Keeping, 245

Drinking Water Regulations, 93

Eutrophication, 64

Chlorine measurement

Amperometric, 73

Factors affecting chlorine disinfection, 170

Filter Backwash Recycle Rule, 104

Filtration, 135, 307

DPD, 73

Free chlorine, 72

Fire Hydrants, 238

Total chlorine, 73

Fires class/classiﬁcations, 265

Flow Control and Isolation Valves, 229

Fluoridation and Deﬂuoridation, 143

Forms of chlorine, 170

Chlorine dosing terms, 175

Chlorine properties, 167

Chlorine reactions related to disinfection,

170

Chlorine residual, 72

Glossary of Pump Calculations Terms, 299

Ground Water Rules, 104

Chlorine storage and safety, 168

Chloroamination, 172

Clariﬁcation/Sedimentation, 133

Clariﬁer Zones, 134

Groundwater, 41

Groundwater Under the Direct Inﬂuence of

Surface Water, 46

Coagulation and Flocculation, 131

Color, 68

Hardness, 70

Testing, 71

Community Conﬁdence Reports, 96

Computer Based Controls and Monitoring,

246

Hardness Removal, 144

Human body component, 34

Contact Time, 176

Infant Methemoglobinemia or blue-baby

syndrome, 65

Corrosion Control, 146, 247

Inorganics, 63

Density, 73, 290

Interim Enhanced Surface Water Treatment

Rule, 98

Detection limit for reporting (DLR), 110

Disadvantages of Chloramines, 174

Disadvantages of Chlorine Dioxide, 179

Disadvantages of ozonation, 180

Disadvantages of UV disinfection, 180

Disinfecting New and Existing Wells, 241

Disinfecting Water Mains, 241

Iron and Manganese Sequestration, 142

Key Components of Chemical Feed System,

151

Lake thermal stratiﬁcation, 48

Lake turnover, 48

Disinfecting Water Storage Tanks, 242

INDEX

377

Lakes and reservoirs classiﬁcation based on

nutrient content, 47

Surface overﬂow rate, 306

Tank volume, 305

Langelier index, 72

Weir loading/overﬂow rate, 307

Unit conversions, 286

Lead and Copper Rule, 106

Lead and Copper Sampling, 246

Long-Term 1 Enhanced Surface Water

Treatment Rule, 98

Temperature conversion, 288

Well hydraulics calculations, 304

Math practice

Area and volume, 314

Blending and dilution, 317

Chemical dosing, 316

Concentration, 315

Long-Term 2 Enhanced Surface Water

Treatment Rule, 98

Maintaining distribution system pressure,

241

Decimals and powers of ten, 311

Density and speciﬁc gravity, 316

Filtration, 319

Math

Area and volume, 284

Averages, 282

Flow and velocity, 315

Percentage, 313

Blending and dilution calculations, 295

Chemical dosing, 293

Concentration, 288

Pounds formula, 316

Pressure, force and head relationships,

317

Contaminant removal efﬁciency, 291

Decimals and powers of ten, 278

Filtration

Pumping power requirements, 318

Pumping rates, 317

Backwashing rates, 309

Backwashing rinse rates, 309

Filter ﬂow rates, 307

Filtration rates, 308

Ratio and proportion, 314

Rounding and signiﬁcant digits, 311

Sedimentation, 319

Totalizing and averages, 312

Unit conversions, 315

Percent product water for

backwashing, 309

Well hydraulics, 318

Flow and velocity, 285

Force, pressure and head, 297

Fractions, 277

Math solution

Pounds formula, 361

Math solutions

Percentage, 281

Pressure, force and head relationship,

366

Pounds formula, 292

Pumping

Filtration, 371

Power requirements for pumping,

303

Pumping power requirements, 367

Pumping rates, 365

Pumping rate calculations, 302

Ratio and proportion, 282

Rounding and signiﬁcant digits, 278

Sedimentation, 305

Sedimentation, 370

Well hydraulics, 369

Metals, 63

Health hazards, 64

Detention time, 306

Microbial and Disinfection Byproducts

378

INDEX

Rules, 104

pH, 71

pH measurement, 72

Microbial contaminants, 66

Microbial testing, 74

Pipelines, 220

Membrane ﬁltration, 78

Piping Material, 222

Polar, 34

Multiple-tube fermentation (MTF), 74

Presence-absence (P-A) method, 79

Quanti-trays tests, 79

Pre-chlorination, 141

Process Basics, 135

Properties of water, 34

Public health goal, 113

Public Notiﬁcation Rule, 109

Tiers 1, 2 and 3, 109

Pump type

National Primary Drinking Water

Regulations, 94

Notiﬁcation levels, 113

Nutrients, 64

Nitrogen and phosphorous, 64

Axial-ﬂow pumps, 195

Centrifugal pumps, 192

Mixed-ﬂow pumps, 195

Operation, 140

Operator

Positive displacement pumps, 195

Rotodynamic pumps, 192

Turbine pumps, 198

Operational activities, 18

Advanced/Reuse, 19

Distribution, 18

Pumping

Treatment, 18

Total dynamic head (TDH), 205

Cavitation, 206

Wastewater, 19

Operator license

Dynamic pressure or Velocity head, 204

Factors contributing to headloss, 204

Force, 202

Qualiﬁcations and eligibility, 20

Water systems operator certiﬁcations,

Glossary of pump calculations terms,

202

Organics, 62

Quantiﬁcation

Head, 203

Biochemical oxygen demand (BOD),

Headloss, 204

Horsepower, 205

OSHA, 263

Pressure, 202

Other Drinking Water Rules, 106

Other Treatment Processes, 141

Ozone, 180

Pump calculations, 202

Pumping calculations, 299

Pumping heads illustration, 207

Static head, 205

Packed Tower Air Stripping, 141

Pathogens

Static pressure, 204

Suction lift, 205

Bacteria, 66

Parasites, 66

Velocity, 204

Cryptosporidium, 66

Giardia, 66

Velocity head, 206

Pumps

Background, 191

Viruses, 66

INDEX

Centrifugal pump components, 200

379

Access and egress, 262

Protective systems, 262

sidewalls slope, 262

Choosing between positive

displacement and centrifugal

pumps, 199

Upper explosive limit (UEL), 267

Water treatment hazards, 259

Safety Practices, 265

Mechanical parts of rotodynamic

pumps, 200

Salts constituents, 64

Radiological contaminants, 62

Radionuclides, 66

Salts found in water and/or used in water

treatment, 65

Measurement

Sampling, 80

picocuries per liter (pCi/L), 66

Radionuclides Rule, 107

Recycled Water, 49

Composite Samples, 80

Grab samples, 80

Holding time, 83

Recycled Water Regulations, 113

Response level, 113

Microbial sampling, 82

Precautions and protocols, 81

Preservative, 83

Revised Total Coliform Rule, 102

Rotating and moving equipment, 263

Sampling methods, 80

Summary of sampling requirements, 83

Sanitary survey, 110

Safety

Chemicals, 259

Elements, 110

Hazards, 260

Frequency, 110

Protection, 260

Chemicals storage, 261

Conﬁned space

Signiﬁcant deﬁciency, 110

Screening, 130

Permit required conﬁned space, 267

Electrical hazards, 261

Falls, 261

SDWA Monitoring, Reporting and

Recordkeeping Requirements, 110

Secondary Drinking Water Regulations, 96

Service Laterals, 222

Fire safety, 265

Hazard control, 259

Hazardous energy, 266

Heat stress, 264

Signiﬁcant consumer notiﬁcation violations,

111

Signiﬁcant monitoring violations, 110

Source Management, 129

Source Water Treatment, 129

Speciﬁc Gravity, 290

Lockout-Tagout (LOTO), 265

Lower explosive limit (LEL), 267

Machine guarding, 264

Material handling ergonomics, 264

Noise, 261

Speciﬁc gravity, 73

Spoils, 263

Personal protective equipment (PPE),

266

Storage Systems, 227

Storage Tank Maintenance, 245

Summary of Disinfectants’ Attributes, 181

Summary of Requirements under Surface

Water Treatment Rules, 98

Safety Data Sheets (SDS), 260

Trench slope, 262

Trenching & excavation, 262

380

INDEX

Surface Water, 47

Certiﬁcation renewal, 27

certiﬁcation requirements, 24

Water quality tests, 67

Water rights, 50

Surface Water Treatment Processes, 129

Surface Water Treatment Rule, 97

Surface Water Treatment Rules, 96

System Disinfection Program, 241

System Flushing Program, 243

Appropriative rights, 51

Prescriptive rights, 51

Riparian rights, 50

Water Sources, 40

Water Supplies, 36

Water Usage Records, 245

Water use, 35

Taste and odor, 68

Temperature, 68

Threshold odor number (TON), 68

Total Coliform Rule, 102

Total dissolved solids, 69

Secondary standard, 69

Trace constituents, 65

Water wells, 44

Wells

Cone of depression, 44

Drawdown, 44

Boron, hormones, EDCs, PCPs, CECs,

PFAS/PFOA, 65

Pumping level, 44

Radius of inﬂuence, 44

Recovery time, 45

Speciﬁc capacity, 44

Static level, 44

Transmission Mains, 220

Trench safety, 263

Turbidity, 67

Typical surface water treatment process, 129

Ultraviolet (UV) disinfection, 179

Types of wells, 45

Dug,driven,drilled wells, 45

Well construction, 45

Well terms, 44

Unregulated Contaminant Monitoring Rule,

Valves Operation and Maintenance, 243

Valves used in Water Distribution, 228

Well types, 45

Wells construction

Borehole, 45

Water cycle, 36

Water Meters, 239

Water Operator

Grout, 46

Zone of inﬂuence, 44

Appendix

XIII

Treatment Exam - ROK . . . . . . . . . . . . . . 377

Distribution Exam - ROK . . . . . . . . . . . . . 389

Wastewater Exams . . . . . . . . . . . . . . . . . . 405

CCR Drinking Water Regs - TOC . . . . . 411

Water Treatment Facilities Classiﬁcation

425

SDS Content - OSHA Guidance . . . . . . 429

Sample SDS . . . . . . . . . . . . . . . . . . . . . . . . 437

A. Treatment Exam - ROK

Expected Range of Knowledge for Drinking Water Treatment Exam

Number of questions by Exam Grade

Content Category

Source Water

Water Treatment Processes

Operation / Maintenance

Laboratory Procedures

Regulations / Administrative Duties

Source Water

Clear Well Storage

Raw Water Storage

Surface Water/Reservoirs

Watershed Protection

Wells/Groundwater

Water Treatment Processes

Coagulation

Sedimentation

Filtration

Disinfection

Corrosion Control

Taste and Odor

Iron and Manganese Removal

Fluoridation

Flocculation

Best Available Technology

Electrical Generators

Operation / Maintenance

Chemical Feeders

Water Meters

Pumps, Motors, and Gearboxes

Blowers and Compressors

Pressure Gauges

Instrumentation

Laboratory Procedures

Sampling

pH Analysis

Fluoride Analysis

General Lab Practices

Disinfectant Analysis

Alkalinity Analysis

Turbidity Analysis

Specific Conductance

Hardness

Color Analysis

Taste and Odor Analysis

Microbiological Analysis

Safety / Regulations / Administrative Duties

Controlling

Organizing

Safety

Directing

Implementing Regulations

Lead and Copper Rule

Planning

Primary Contaminants

Recordkeeping

Secondary Contaminants

Total Coliform Rule

California Waterworks Standards

Operator Certification Regulations

Safe Drinking Water Act & Amendments

Surface Water Treatment Rule and Amendments

Expected Range of Knowledge for Drinking Water Treatment Exam

The tables below list specific objectives in each content category. The specific exam grades

where these objectives are included are also provided below.

Source Water

T1 - T4

Ability to calculate flow rates and water velocity

Ability to calculate the volume of water in a storage facility

Ability to calculate well drawdown

Ability to calculate detention time

Ability to calculate well specific capacity

Ability to calculate well head pressure

Ability to convert common water units (e.g. gallons per minute to MGD)

Ability to convert head pressure to water elevation

Ability to convert units of length, volume, flow and pressure

Ability to determine water level in a storage tank, reservoir, or well

Ability to recognize abnormal chemical characteristics of water

Ability to recognize abnormal odors or colors

Ability to recognize abnormal well operations

Ability to recognize potential security risks

Ability to recognize potential sources of contamination in surface water

Ability to recognize the influence of surface water on a groundwater source

Knowledge of chemicals that contribute alkalinity and hardness to water

Knowledge of common chemical and microbial contaminants in raw water

Knowledge of flow measurement devices

Knowledge of potential microbial and chemical contamination sources in groundwater

and surface water

T1 - T4

T2 - T4

Knowledge of problems caused by hard water

Knowledge of storage tank disinfection procedures

Knowledge of the characteristics of aquifers

Knowledge of the chemical components of groundwater and surface water

Knowledge of the hydrologic cycle

Knowledge of visual signs of contamination in a surface water reservoir

Knowledge of well components

Knowledge of well depth measurement procedures

Knowledge of well disinfection procedures

Knowledge of well drawdown measurement techniques

Ability to discriminate between normal and abnormal conditions of a surface water

reservoir

T2 - T4

Ability to recognize hydrological changes

Knowledge of how reservoir intake level effects water quality

Knowledge of the effects of seasonal changes on water reservoirs

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

T2 - T4

T3 - T4

Knowledge of pretreatment procedures

Knowledge of surface water reservoir stratification

Ability to recognize head loss across an intake screen

Knowledge of groundwater treatment procedures

Water Treatment Processes

Coagulation/Flocculation/Sedimentation

T3 - T4

Ability to calculate a coagulant dose from a jar test

Ability to perform a jar test

Ability to recognize and correct abnormal conditions in a sedimentation basin

Ability to recognize normal and abnormal floc formation

Knowledge of flocculation tanks

Knowledge of chemical coagulants and coagulant aids

Knowledge of coagulation/flocculation start-up/shutdown and adjustment procedures

Knowledge of enhanced coagulation

Knowledge of sedimentation basins

Knowledge of the coagulation/flocculation process

Knowledge of the effects of temperature, alkalinity, and pH on flocculation

Knowledge of the flash mixing process

Knowledge of the jar testing procedure

Knowledge of the sedimentation process

Knowledge of tube settlers

Knowledge of water gradient velocities

Knowledge of the zeta potential

Knowledge of Van Der Waals forces

Knowledge of ballasted flocculation procedures

Filtration

T1 - T4

T2 - T4

T3 - T4

Ability to interpret turbidity information

Knowledge of turbidity causing matter

Ability to calculate daily filter production

Ability to calculate filter backwash rate

Knowledge of head loss effects on filters

Knowledge of filter surface washing methods

Knowledge of filtration mechanisms (absorption, adsorption)

Ability to calculate a filter-aid dosage

Ability to calculate a filtration rate

Ability to calculate filter loading rate

Ability to recognize and correct problems in gravity filters

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

T3 - T4

Ability to recognize and correct problems in multimedia filters

Knowledge of backwash sequencing

Knowledge of filter media types and uses

Knowledge of maximum filtration rates

Knowledge of normal and abnormal filter media conditions

Ability to calculate filter media volume and capacity

Ability to conduct a comprehensive performance evaluation of a filter

Ability to operate an air scour system

Ability to perform a filter assessment surveillance program

Ability to perform a filter profile analysis

Ability to recognize and correct problems in granular activated carbon filters

Knowledge of air scouring systems

Knowledge of filter media replacement requirements and techniques

Knowledge of filter porosity

Disinfection

T1 - T4

T2 - T4

Ability to calculate a chemical dosage

Ability to calculate a chemical solution concentration

Ability to calculate chlorine demand and chlorine residual

Knowledge of acceptable chlorine residual levels

Knowledge of breakpoint chlorination chemistry

Knowledge of chlorine chemistry

Knowledge of common chlorine compounds used for disinfection

Knowledge of disinfectant byproduct formation

Knowledge of disinfectant properties and uses

Knowledge of disinfection residual requirements

Knowledge of MCLs and MRDLs of disinfectants

Ability to calculate a CT value

Ability to choose an appropriate disinfectant for a specific microbial problem

Knowledge of chloramine chemistry

Knowledge of disinfectant byproduct reduction procedures

Knowledge of TOC/Disinfection byproduct correlation

Corrosion Control

T1 - T4

T2 - T4

T3 - T4

Ability to recognize corrosion problems

Knowledge of pH adjustment procedures

Knowledge of corrosion causes

Knowledge of corrosion reduction methods

Knowledge of C-factor

Knowledge of the cathodic protection process

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

T3 - T4

Knowledge of corrosion control inhibitors

Knowledge of the Langelier Index

Knowledge of corrosion control chemical reactions

Ability to choose the proper corrosion control chemical for a specific problem

Taste and Odor

T1 - T4

Knowledge of abnormal taste and odors

Knowledge of chemicals that contribute taste and odor

Knowledge of taste and odor treatment processes

Iron and Manganese

T1 - T4

T3 - T4

Ability to recognize an iron and manganese problem

Knowledge of iron and manganese oxidation chemistry

Knowledge of iron and manganese removal techniques

Fluoridation

Knowledge fluoridation chemicals

Knowledge of fluoride chemistry

Knowledge of optimal fluoride level range

Knowledge of the health effects of fluoride

Best Available Technology (BAT)

T1 - T4

T2 - T4

T3 - T4

Knowledge of health effects of lead and copper

Knowledge of adverse health effects caused by common contaminants

Knowledge of Best Available Technology (BAT) for common water contaminants

Knowledge of effective removal techniques for common contaminants

Ability to perform blending calculations

Knowledge of the aeration process

Knowledge of chemical oxidation techniques and uses

Knowledge of granular activated carbon (GAC)

Knowledge of nitrate removal processes

Operation / Maintenance

Chemical Feeders

T1 - T4

Ability to calculate a dosage for a chemical feeder

Ability to calibrate and adjust a chemical feeder pump

Ability to operate a chemical feeder system

Ability to replace components of a chemical feeder system

Ability to set proper chemical feed rate

Knowledge of chemical feeder calibration and adjustment

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

T1 - T4

Knowledge of the components of chemical feeder systems

Knowledge of the operation of chemical feeder systems

Pumps, Motors, and Gearboxes

T1 - T4

T2 - T4

Ability to discriminate between normal and abnormal operation of a water pump

Knowledge of pump types and uses

Knowledge of the components of a water pump

Knowledge of the operation of a water pump

Knowledge of valve types and uses

Ability to replace components of a water pump

Knowledge of pump installation procedures

Blowers and Compressors

T3 - T4

Knowledge of the operation of blowers and compressors

T3 - T4

Ability to discriminate between normal and abnormal operation of blowers and

compressors

Ability to replace components of blowers and compressors

Knowledge of the components of blowers and compressors

Water Meters

T1 - T4

Ability to read and interpret water meter readings

Knowledge of the components of water meters

Knowledge of the operation of water meters

Knowledge of water meter types and uses

Ability to calibrate a water meter

T1 - T4

T2 - T4

Pressure Gauges

T1 - T4

T2 - T4

T3 - T4

Knowledge of head pressure

Knowledge of the operation of pressure gauges

Ability to replace pressure gauges

Knowledge of the components of pressure gauges

Instrumentation

T1 - T4

T2 - T4

T3 - T4

Knowledge of basic SCADA system components

Ability to determine normal operation of a SCADA system

Knowledge of the components of on-line analyzers

Ability to recognize analytical interferences in on-line analyzers

Ability to repair or replace defective parts of on-line analyzers

Knowledge of the operation of on-line analyzers

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

Electrical Generators

T3 - T4

Knowledge of the operation of an electrical generator

T3 - T4

Knowledge of the components of an electrical generator

Laboratory Procedures

Sampling

T1 - T4

Ability to collect a water sample

Ability to determine a proper sampling site

Ability to follow chain of custody

Knowledge of appropriate sample containers and sample sizes

Knowledge of maximum holding times

Knowledge of proper sampling and preservation techniques

Knowledge of well sampling techniques

General Laboratory Practices

T1 - T4

T2 - T4

Ability to calculate a chemical solution concentration

Knowledge of chemical hazards

Ability to calculate a dilution factor

Ability to mix chemicals and prepare reagents

Ability to perform dilutions

Disinfectant Analysis

T1 - T4

Ability to analyze a water sample for free and total chlorine

Ability to read and interpret a colorimeter

Knowledge of approved analytical procedures for chlorine analysis

Knowledge of chlorine chemistry

Alkalinity Analysis

T2 - T4

T3 - T4

Knowledge of chemicals that contribute alkalinity to water

Ability to use a titrator

Ability to recognize a titration endpoint

Knowledge of abnormal alkalinity levels

pH Analysis

T1 - T4

Ability to read and interpret a pH meter

Knowledge of acids and bases

T1 - T4

Knowledge of acceptable water pH range

Knowledge of chemicals that affect the pH of water

Knowledge of the effects of pH on water quality

Knowledge of the pH scale

T1 - T4

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

T1 - T4

T2 - T4

Ability to analyze a water sample for pH

Ability to calibrate a pH meter

Turbidity Analysis

T1 - T4

T1 T4

T2 - T4

Ability to analyze a water sample for turbidity

Ability to read and interpret a turbidimeter

Knowledge of the Nephelometric Turbidity Unit (NTU) scale

Knowledge of turbidimeter instrumentation

Knowledge of turbidity causing matter

Knowledge of turbidity level requirements

Ability to prepare and calibrate turbidimeter with Primary Standard (Formazin)

Specific Conductance

T3 - T4

Ability to analyze a water sample for specific conductance

Ability to read and interpret a specific conductance meter

Ability to calculate a TDS value from a specific conductance reading

Knowledge of EC/TDS ratio

Ability to calibrate a specific conductance meter

Hardness

T1 - T4

Knowledge of chemicals that contribute hardness to water

Ability to analyze a water sample for water hardness

Knowledge of hardness removal processes

T2 - T4

Fluoride Analysis

Ability to operate an Ion Specific Electrode (ISE)

Knowledge of optimal fluoride level range

Color Analysis

T2 - T4

T3 - T4

Ability to recognize abnormal colors in water

Knowledge of abnormal color levels

Knowledge of color analysis scale

Knowledge of true and apparent color

Taste and Odor Analysis

T1 - T4

Ability to identify an objectionable taste or odor in water

Knowledge of chemicals that contribute taste and odor to water

Knowledge of odor analysis protocol

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

Microbiological Analysis

T1 - T4

T2 - T4

T3 - T4

Knowledge of the presence/absence test method

Knowledge of approved analytical procedures for coliform analysis

Knowledge of common microbial contaminants in raw water

Knowledge of Heterotrophic Plate Count (HPC)

Ability to distinguish between presumptive and confirmed coliform results

Knowledge of the multiple tube fermentation method

Knowledge of the membrane filtration method

Safety / Regulations / Administrative Duties

Safety

T1 - T4

T2 - T4

T3 - T4

Ability to demonstrate safe work habits

Ability to identify potential safety hazards

Ability to recognize unsafe working conditions

Ability to select and utilize safety equipment

Knowledge of chemical hazards

Knowledge of compressed gas safety procedures

Knowledge of confined space safety procedures

Knowledge of electrical safety

Knowledge of hazardous chemical handling

Knowledge of incompatible chemicals

Knowledge of lock-out/tag-out procedures

Knowledge of Material Safety Data (MSD) sheets

Knowledge of personal protective equipment (PPE)

Knowledge of proper chemical handling techniques

Knowledge of safe working practices

Knowledge of the use of safety equipment

Knowledge of HAZWOPER guidelines

Ability to administer a safety plan

Ability to generate a written safety plan

Regulations / Administrative Duties

T1 - T4

Ability to interpret water quality characteristics (hardness, turbidity, pH)

Knowledge of basic unit processes used in treating drinking water

Knowledge of corrective actions to take when regulations are violated

Knowledge of drinking water monitoring and reporting requirements

Knowledge of drinking water regulations

Knowledge of notification protocol and procedures

Knowledge of NSF Standards

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

T1 - T4

T2 - T4

Knowledge of operator certification requirements

Knowledge of Primary and Secondary Drinking Water Standards

Knowledge of public notification procedures

Knowledge of record keeping requirements

Knowledge of California Waterworks Standards

Knowledge of the Consumer Confidence Report (CCR)

Knowledge of the Disinfectants and Disinfection Byproduct Rule and amendments

Knowledge of the Groundwater Rule

Knowledge of the Lead and Copper Rule

Knowledge of the Surface Water Treatment Rule and amendments

Knowledge of the Total Coliform Rule and amendments

Knowledge of waterborne pathogens

Ability to interpret water quality reports

Ability to research and interpret Maximum Contaminant Levels (MCLs)

Ability to administer a maintenance program

Knowledge of cryptosporidium action plan

Knowledge of pending regulations

Knowledge of performance standards and removal requirements for surface water

treatment

T2 - T4

T3 - T4

Knowledge of the Filter Backwash Rule

Knowledge of routine sampling requirements

Ability to administer a regulatory compliance program

Ability to calculate percent or log removal of contaminants from water

Ability to calculate the cost of water treatment operations

Ability to develop an operational site sampling plan

Ability to develop an operations plan

Ability to evaluate treatment facility performance

Knowledge of facility operation and maintenance

Knowledge of management principles

Knowledge of permit requirements for water operations

Knowledge of principles of supervision

Knowledge of public relations principles

Knowledge of pump to waste discharge environmental regulations

Knowledge of regulatory primacy issues

Knowledge of source water replenishment processes

Knowledge of the Sanitary Survey process

Ability to interpret historical water use data

Knowledge of the role of Regional Boards in managing contamination sources

Knowledge of the Source Water Assessment Program

Knowledge of the Watershed Survey process

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Treatment Exam

Knowledge of the vulnerability assessment process

Water Treatment Exam Math

T1 - T4

T2 - T4

T3 - T4

Ability to calculate flow rates and water velocity

Ability to calculate the volume of water in a storage facility

Ability to calculate well drawdown

Ability to calculate detention time

Ability to calculate well specific capacity

Ability to calculate well head pressure

Ability to convert common water units, (gallons per minute to MGD, etc…)

Ability to convert head pressure to water elevation

Ability to convert units of length, volume, flow and pressure

Ability to determine water level in a storage tank, reservoir or well

Ability to calculate a chemical dosage

Ability to calculate a chemical solution concentration

Ability to calculate chlorine demand and chlorine residual

Ability to calculate a dosage for a chemical feeder

Ability to calculate a chemical solution concentration

Ability to calculate daily filter production

Ability to calculate filter backwash rate

Ability to calculate a CT value

Ability to calculate a dilution factor

Ability to perform dilutions

Ability to calculate a coagulant dose from a jar test

Ability to calculate a filter-aid dosage

Ability to calculate a filtration rate

Ability to calculate filter loading rate

Ability to calculate percent or log removal of contaminants from water

Ability to calculate the cost of water treatment operations

Rev. 4/2020

B. Distribution Exam - ROK

Expected Range of Knowledge for Drinking Water Distribution Exam

Number of questions by Exam Grade

Content Category

Disinfection

Distribution System Design / Hydraulics

Equipment Operation / Maintenance /

Inspections

Drinking Water Regulations / Management /

Safety

Water Mains and Piping

Water Quality / Water Source

Disinfection

Water Main Disinfection

Well Disinfection

Chloramination

Chlorine Curve Chemistry

Types of Disinfectants

Disinfectant By-Products

Storage Reservoir Disinfection

Distribution System Design / Hydraulics

System Layout

Assess System Demand

Water Hammer

Storage Facilities

Service Connections

Systems Map

Flow Rates and Velocity

Head Loss

Cavitation

Water Pressure and Volume

Static and Dynamic Pressure

Cross-Connection and Backflow Devices

Equipment Operation / Maintenance / Inspections

Valves

Corrosion

Pump Types, Uses, and Sizes

Water Horsepower

Wells (New and Abandoned)

Water Meters

In-Line Sensors

Power Generators

SCADA

Hydrants

Chemical Feeders

Equipment Installation and Repair

Troubleshoot and Repair Pumps and Motors

Inspection of Water Mains, Piping, Storage Tanks

Drinking Water Regulations / Management / Safety

Disinfection-By-Product Rule

Lead and Copper Rule

Safe Drinking Water Act

Total Coliform Rule

Maintenance Plan

Safety Plan

MCLs

Public Notification

Emergency Response Planning

Future Planning

Water Conservation Planning

Water Rates

Administer Compliance, Budgets

Monitoring and Sampling Requirements

Operator Certification Regulations

Expected Range of Knowledge for Drinking Water Distribution Exam

Water Mains and Pumping

Cleaning and Maintenance

Excavation

Joints and Fittings

Leak Detection and Repair

Pipe Selection

Service Line Installation

Sanitary Survey

Installation and Repair

Water Quality / Water Sources

Coliform Group

Corrosivity

Unidirectional Flushing

Waterborne Diseases

Groundwater and Wells

Heterotrophic Bacteria

Organic and Inorganic Compounds

pH, Conductivity, Hardness, and Turbidity

The tables below list specific objectives in each content category. The specific exam grades

where these objectives are included are also provided below.

Disinfection

Water Main Disinfection

D1 - D5

Knowledge of water main disinfectant techniques

Knowledge of dechlorination techniques

Ability to apply disinfectant

Knowledge of AWWA disinfection standards for water mains

Well Disinfection

D1 - D5

Knowledge of contamination sources in a well

Ability to calculate a disinfectant dosage

Knowledge of well disinfection techniques

Knowledge of water depth measurement techniques

Knowledge of AWWA disinfection standards for wells

Ability to measure the water depth in a well

Ability to calculate the volume of a well

Storage Reservoir Disinfection

D1 - D5

D2 - D5

D3 - D5

Knowledge of water storage contamination sources

Ability to calculate the volume of a storage reservoir

Knowledge of storage reservoir disinfection techniques

Knowledge of AWWA disinfection standards for storage facilities

Ability to calculate a disinfectant dosage

Ability to choose the proper disinfectant technique

Ability to calculate the surface area of the interior walls of a storage reservoir

Ability to calculate CT

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

Disinfectant By-Products

D2 - D5

D3 - D5

Knowledge of the causes of DBPs

Knowledge of DBP reduction methods

Knowledge of DBP formation

Knowledge of DBP compounds

Ability to recognize abnormal levels of DBPs in the water distribution system

Chloramination

D1 - D5

D2 - D5

Ability to measure total chlorine

Knowledge of the chlorine curve

Knowledge of advantages/disadvantages of chloramination

Knowledge of chloramine compounds

Ability to calculate chlorine/ammonia ratio for chloramination

Chlorine Curve Chemistry

D2 - D5

Knowledge of the definition of breakpoint chlorination

Knowledge of the chlorine curve

Ability to recognize when breakpoint has been met

Types of Disinfectants

D1 - D5

D2 - D5

D3 - D5

Knowledge of the purpose of disinfection

Knowledge of contact time

Knowledge of causes of chlorine demand

Ability to monitor and interpret chlorine residual

Ability to calculate a dosage

Knowledge of disinfectant types and characteristics

Knowledge of factors affecting chlorine disinfection

Knowledge of chlorine analysis techniques

Knowledge of chlorine chemistry

Distribution System Design / Hydraulics

Assess System Demand

D1 - D5

Knowledge of unit conversions

D2 - D5

Knowledge of the terms, “peak demand,” “peak hour demand,” “maximum daily

demand,” and “per-capita demand”

Cross-Connection and Backflow Devices

D1 - D5

Knowledge of conditions that cause backflow

Knowledge of available backflow prevention methods

Knowledge of “back-pressure” and “back-siphonage” conditions

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

D1 - D5

Ability to recognize a potential backflow hazard

Ability to recognize a cross-connection

Service Connections

D1 - D5

D2 - D5

Knowledge of service connection materials and fittings

Ability to tap a water main

Knowledge of recordkeeping requirements

Storage Facilities

D1 - D5

D2 - D5

Ability to calculate the volume of a storage facility

Ability to calculate flow rates for a storage facility

Knowledge of the types of storage facilities and their applications

Knowledge of storage facility corrosion control methods

Knowledge of storage facility components

Ability to drain, clean, and disinfect a storage facility

System Layout

D1 - D5

D2 - D5

D4 - D5

Knowledge of “grid,” “tree,” “arterial,” and “dead end” water systems

Ability to differentiate between a “trunk” line and a “transmission” line

Ability to calculate a hydraulic gradient

System Maps

D1 - D5

Knowledge of pressure/elevation relationships

Knowledge of map types

D2 - D5

Ability to interpret map symbols

D2 - D5

Ability to convert a scale to actual distance

Flow Rates and Velocity

D1 - D5

D2 - D5

Ability to convert units of volume, area, and time

Ability to calculate the volume of a pipe

Ability to calculate the area of a pipe cross-section

Ability to calculate a flow rate

Ability to calculate water velocity

Head Loss

D2 - D5

Knowledge of the relationship between head loss and friction

Knowledge of the effect of corrosion on head loss

D3 - D5

Cavitation

D2 - D5

Knowledge of the causes of cavitation

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

D2 - D5

Ability to recognize the signs of cavitation

Water Hammer

D1 - D5

D2 - D5

Knowledge of water hammer reduction techniques

Knowledge of the definition of water hammer

Knowledge of the causes of water hammer

Ability to calculate the surface area of a valve face

Ability to calculate total force on a valve

Water Pressure and Volume

D1 - D5

Ability to convert units of volume, pressure and area

D1 - D5

Ability to calculate the volume of a cylinder, rectangle, and square

Static and Dynamic Pressure

D1 - D5

Knowledge of the relationship between water velocity and water pressure

Ability to recognize abnormal pressure readings (too high or too low)

Ability to read and interpret a pressure gauge

Ability to convert pressure to feet of head

Equipment Operation / Maintenance / Inspections

Valves

D1 - D5

D2 - D5

Knowledge of proper valve installation

Knowledge of valve types and applications

Knowledge of the principles of operation of valves

Knowledge of pressure regulating valve maintenance

Ability to recognize a malfunctioning valve

Knowledge of pressure ratings

Water Meters

D1 - D5

Knowledge of water meter types and purposes

Ability to convert water units

D1 - D5

Ability to choose the correct meter size

Knowledge of mechanical parts of water meters

D2 - D5

Hydrants

D1 - D5

Knowledge of thrust blocks

Knowledge of pressure requirements

Knowledge of mechanical parts of hydrants

Knowledge of hydrant types

Ability to flush using a hydrant

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

Chemical Feeders

D1 - D5

D2 - D5

Ability to read a graduated cylinder

Ability to calculate a dosage

Knowledge of chemical feeder types

Knowledge of chemical feeder components

Ability to troubleshoot a chemical feeder

Corrosion

D2 - D5

D3 - D5

Knowledge of type and applications of cathodic protection devices

Knowledge of the galvanic series

Knowledge of principles of operation of cathodic protection devices

In-Line Sensors

D2 - D5

Knowledge of required reagents and standards

Knowledge of analysis methods

Ability to recognize normal operation of in-line sensors

Power Generators

D1 - D5

D4 - D5

Knowledge of start-up procedures

Knowledge of basic operation

Knowledge of power requirements (e.g. efficiency)

SCADA

D2 - D5

Knowledge of the components of a SCADA system

Knowledge of communication techniques

Ability to interpret SCADA information

Pump Types, Uses, and Sizes

D1 - D5

D2 - D5

D3 - D5

Knowledge of pump types

Knowledge of operational principles of a water pump

Ability to match pump type to application

Ability to interpret a pump curve

Troubleshoot and Repair Pumps and Motors

D1 - D5

D2 - D5

D3 - D5

Ability to recognize abnormal pump operating conditions

Knowledge of the mechanical components of pumps and motors

Knowledge of pump maintenance procedures

Ability to repair and replace pump and motor system components

Knowledge of recordkeeping requirements

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

D3 - D5

Knowledge of when to “MEG” a motor

Water Horsepower

D3 - D5

D4 - D5

Ability to calculate pump efficiency

Ability to calculate brake-horsepower

Ability to calculate the cost of pumping water

Inspection of Water Mains and Piping

D1 - D5

D2 - D5

Knowledge of proper backfill procedures and compaction

Knowledge of proper bedding techniques

Knowledge of pipe connectors and applications

Knowledge of compatible materials

Ability to recognize faulty or damaged pipe

Ability to recognize abnormal operating conditions

Knowledge of proper thrust restraint

Knowledge of proper disinfection techniques

Knowledge of allowable leak loss

Inspection of Storage Tanks

D1 - D5

D3 - D5

Knowledge of security procedures/measures

Knowledge of safety equipment requirements

Knowledge of storage tank corrosion control measures

Inspection of Equipment Installation and Repair

D1 - D5

D2 - D5

D3 - D5

Knowledge of proper valve installation

Knowledge of proper hydrant installation

Knowledge of hydrant valve operation/testing

Knowledge of thrust restraint requirements

Knowledge of packing gland settings

Knowledge of proper pump alignment

Knowledge of proper phase balance

Inspection of Wells (New and Abandoned)

D1 - D5

D2 - D5

D3 - D5

D4 - D5

Ability to calculate draw down

Knowledge of proper installation of a sanitary seal on a well

Ability to calculate specific yield

Knowledge of well abandonment procedures and permit requirements

Knowledge of proper gravel packing and screen depth

Knowledge of permit requirements

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

Drinking Water Regulations / Management / Safety

Disinfection By-Product Rule

D2 - D5

D3 - D5

Knowledge of Disinfection By-Product Rule sampling requirements

Knowledge of Disinfection By-Product Rule reporting requirements

Knowledge of Disinfection By-Product Rule MCL requirements

Lead and Copper Rule

D1 - D5

D3 - D5

D4 - D5

Ability to take a lead and copper sample

Knowledge of lead and copper sampling requirements

Knowledge of lead and copper rule reporting requirements

Ability to recognize a lead and copper rule violation

Maximum Contaminant Levels (MCL)

D1 - D5

D2 - D5

Knowledge of the definition of MCL

Knowledge of maximum disinfectant residual level for chlorine

Ability to differentiate between a primary and secondary MCL

Ability to recognize MCL violations

Monitoring and Sampling Requirements

D1 - D5

Ability to read a sample siting plan

D1 - D5

Knowledge of water sampling techniques for bacteriological, organic, and inorganic

constituents

D1 - D5

Knowledge of holding times (e.g. preservatives)

Operator Certification Regulations

D1 - D5

Knowledge of certification requirements

Public Notification

D1 - D5

D4 - D5

Knowledge of acute violations

Knowledge of when public notification is required

Knowledge of required language to use

Knowledge of notification paths (e.g. newspaper, electronic)

Safe Drinking Water Act (SDWA)

D1 - D5

D2 - D5

D3 - D5

Knowledge of the purpose of the SDWA

Knowledge of the major components of the SDWA

Knowledge of reporting and recordkeeping requirements

Knowledge of non-compliance penalties

Total Coliform Rule

D1 - D5

Knowledge of Total Coliform Rule sampling requirements

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

D1 - D5

Knowledge of Total Coliform Rule reporting requirements

Administer Compliance, Budgets

D1 - D5

D3 - D5

Knowledge of OSHA/Cal-OSHA safety regulations

Knowledge of CDPH Water Quality regulations

Ability to calculate the cost of water production

Knowledge of RWQCB discharge requirements

Knowledge of Air Quality Management regulations

Knowledge of the components of a budget (e.g. revenues, expenditures, risk

management, insurance costs, depreciation)

Knowledge of O&M budget components (e.g. labor, professional services, supplies,

energy, water, capital improvement)

Emergency Response Planning

D1 - D5

D2 - D5

D3 - D5

Knowledge of the components of the Emergency Response Plan

Knowledge of system pressure zones

Knowledge of AWWA disinfection standards

Knowledge of the vulnerability assessment

Knowledge of public notification requirements

Ability to train personnel on emergency response procedures

Ability to perform damage assessment and recovery planning

Future Planning

D4 - D5

Knowledge of long-term water availability

Knowledge of capital improvement/capital replacement requirements

Ability to estimate future water needs

Maintenance Plan

D1 - D5

D2 - D5

Knowledge of predictive, preventative, and corrective maintenance

Knowledge of maintenance recordkeeping

Knowledge of the fire hydrant testing program

Knowledge of valve exercise program

Safety Plan

D1 - D5

Knowledge of the elements of a safety program (e.g. policy statement, training,

promotion, accident investigation, reporting)

D1 - D5

D3 - D5

D4 - D5

Knowledge of safety regulation requirements (e.g. IIPP)

Knowledge of recordkeeping/reporting requirements to OSHA

Ability to develop and implement a safety plan

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

Water Conservation Planning

D3 - D5

D4 - D5

Knowledge of energy conservation methods

Ability to conduct a water audit

Ability to calculate water production costs

Ability to calculate a water loss rate

Water Rates

Knowledge of water use projection methods

Knowledge of water rate structures, water rate setting methods

Knowledge of local water usage patterns

Ability to calculate annual expenditures

Safety

D1 - D5

Knowledge of trenching safety equipment and procedures

Knowledge of traffic control procedures

Knowledge of personal safety equipment and procedures

Knowledge of hazardous material safety equipment and handling

Knowledge of fire safety equipment and procedures

Knowledge of electrical safety equipment and procedures

Knowledge of confined space safety equipment and procedures

Knowledge of chemical handling safety equipment and procedures

Knowledge of AC pipe handling procedures

Knowledge of the relapse cycle

Ability to recognize a confined space

Water Mains and Piping

Cleaning and Maintenance

D1 - D5

D2 - D5

D3 - D5

Knowledge of proper flushing procedures

Knowledge of notification requirements

Ability to set up a temporary service line

Knowledge of the causes and effects of tuberculation

Knowledge of pipe cleaning procedures

Ability to recognize tuberculation

Ability to choose the proper cleaning technique

Excavation, Installation, and Repair

D1 - D5

Knowledge of bedding techniques

D1 - D5

Knowledge of proper backfill techniques

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

D1 - D5

D2 - D5

Knowledge of notification requirements

Knowledge of excavating techniques

Knowledge of compaction tools and methods

Knowledge of Cal-OSHA trenching and shoring requirements

Ability to operate a dewatering pump

Ability to connect water pipe

Ability to calculate the volume of a trench

Knowledge of dewatering techniques

Ability to identify different soil types

Joints and Fittings

D1 - D5

D2 - D5

Knowledge of proper joints and fitting applications

Knowledge of pipe fitting and joining methods

Knowledge of proper thrust block uses

Ability to choose the correct type of joint

Ability to calculate thrust block size

Leak Detection and Repair

D1 - D5

D2 - D5

Knowledge of pipe locating methods

Knowledge of leak detection methods

Knowledge of factors affecting leak detection

Pipe Selection

D1 - D5

D2 - D5

D3 - D5

Knowledge of pipe material and applications

Knowledge of pipe material compatibility

Knowledge of advantages/disadvantages of pipe materials

Knowledge of C-Factor

Ability to calculate the velocity of water

Ability to calculate pipe capacity

Knowledge of flow demand requirements

Service Line Installation

D1 - D5

D2 - D5

Knowledge of material compatibility

Ability to flush a service line

Ability to differentiate pipe tap size

Ability to differentiate meter size

Ability to calculate pipe volumes

Knowledge of tapping tools/equipment

Knowledge of tapping methods

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

Water Quality / Water Sources

Coliform Group

D1 - D5

D2 - D5

Knowledge of the definition of pathogenic organisms

Knowledge of coliform bacteria types

Knowledge of coliform analysis methods

Ability to interpret coliform test results

Knowledge of the use of coliform as a surrogate

Determination of Corrosivity

D2 - D5

D3 - D5

D4 - D5

Ability to recognize corrosive conditions in distribution systems

Knowledge of the effect of corrosion in a distribution system

Knowledge of the causes of corrosion in a distribution system

Knowledge of the relationship between corrosion and lead/copper concentrations

Knowledge of the Langelier Index

Knowledge of corrosion control techniques

Ability to interpret a Langelier Index

Heterotrophic Bacteria

D2 - D5

Knowledge of the effects of heterotrophic bacteria in a distribution system

D2 - D5

Knowledge of heterotrophic bacteria

Organic and Inorganic Contaminants

D1 - D5

D2 - D5

D3 - D5

Knowledge of the impacts of high nitrate concentrations in a distribution system

Knowledge of nitrate formation in a distribution system

Knowledge of sources of organic contaminants in a distribution system

Knowledge of sources of inorganic contaminants in a distribution system

Knowledge of common organic contaminant compounds

Knowledge of common inorganic contaminant compounds

pH, Conductivity, Hardness, and Turbidity

D1 - D5

D2 - D5

Knowledge of the meaning of high levels of turbidity in a distribution system

Knowledge of normal pH range in drinking water

Ability to recognize abnormal turbidity levels in a distribution system

Ability to recognize abnormal pH levels of water in a distribution system

Knowledge of the effects of hardness in a distribution system

Knowledge of the effects of abnormal pH levels in a distribution system

Unidirectional Flushing

D1 - D5

Knowledge of the impacts of flushing on a distribution system

D1 - D5

Knowledge of proper flushing velocities

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

D1 - D5

D2 - D5

D3 - D5

Knowledge of equipment used for flushing

Knowledge of flushing techniques

Ability to recognize when flushing is required

Ability to calculate a water velocity

Knowledge of permit requirements for flushing

Waterborne Diseases

D2 - D5

Knowledge of potential waterborne diseases

D2 - D5

Ability to distinguish between presumptive and confirmed results

Groundwater and Wells

D1 - D5

D2 - D5

D3 - D5

D4 - D5

Knowledge of the hydrologic cycle

Ability to measure well depth

Knowledge of zone of influence

Knowledge of well protection

Knowledge of well components and terms

Knowledge of water table fluctuations

Knowledge of static and pumping water level

Knowledge of recovery time

Knowledge of cone of depression

Ability to recognize potential sources of contamination

Ability to convert a pressure reading to depth of water

Knowledge of well location requirements

Knowledge of the chemical components of groundwater

Knowledge of the characteristics of aquifers

Sanitary Survey

D1 - D5

Ability to recognize potential sources of contamination

D4 - D5

Knowledge of sanitary survey requirements

Water Distribution Exam Math

D1 - D5

Ability to convert water units

Ability to convert units of volume, area, pressure, and time

Ability to convert pressure to feet of head

Ability to calculate a disinfectant dosage

Ability to measure the water depth in a well

Ability to calculate the well draw down

Ability to calculate the volume of a cylinder, rectangle, and square

Ability to calculate the volume of a well, storage reservoir, pipe, trench

Ability to calculate flow rates

Rev. 4/2020

Expected Range of Knowledge for Drinking Water Distribution Exam

D1 - D5

D2 - D5

D3 - D5

D4 – D5

Ability to calculate the area of a pipe cross-section

Ability to calculate the surface area of a valve face

Ability to calculate total force on a valve

Ability to calculate water velocity

Ability to calculate pipe capacity

Ability to calculate the surface area of the interior walls of a storage reservoir

Ability to convert a scale to actual distance

Ability to convert a pressure reading to depth of water

Ability to calculate chlorine/ammonia ratio for chloramination

Ability to calculate thrust block size

Ability to calculate specific yield of a well

Ability to calculate CT

Ability to calculate pump efficiency

Ability to calculate brake-horsepower

Ability to calculate the cost of water production

Ability to calculate the cost of pumping water

Ability to estimate future water needs

Ability to calculate the hydraulic gradient

Ability to calculate water production costs

Ability to calculate a water loss rate

Ability to calculate annual expenditures

Rev. 4/2020

C. Wastewater Exams

GRADE I

WWTP OPERATOR

EXAMINATION INFORMATION

The Grade I examination contains questions regarding the following subjects: basic

safety practices, hazards encountered during wastewater treatment plant operations,

sampling and simple analysis of wastewater constituents, operation and maintenance

procedures in preliminary and primary treatment unit processes, anaerobic sludge

digestion and disinfection.

It also includes specific questions on the operation and maintenance of wastewater

stabilization ponds and state regulations regarding the classification of wastewater

treatment plants and operator certification.

The Grade I examination also contains mathematical questions. Examinees may be

asked to calculate a variety of problems including chlorine demand/residual, overflow

rates, removal efficiency (% removal), pumping rate, solids concentration, detention

time, hydraulic or organic loading rates and volume or surface area. The examinee

should be familiar with typical calculations related to the subject matter listed in

paragraph 1.

Examinees are given 2 ½ hours to complete the examination. The question format is as

follows:

45 True/False Questions

25 Multiple Choice Questions

10 Math Problems

1 point each

2 points each

4 points each

TOTAL POINTS 135

Passing Score: To pass, you must achieve:

(a) a minimum total score of 94.5 points (70 percent), AND

(b) a score of at least 20 points (50 percent) on the ten Math Questions.

GRADE II

WWTP OPERATOR

EXAMINATION INFORMATION

The Grade II examination contains questions regarding the following subjects: basic

safety practices, hazards encountered during wastewater treatment plant operations,

sampling and simple analysis of wastewater constituents, and operation and

maintenance procedures in preliminary and primary treatment unit processes, anaerobic

sludge digestion and disinfection.

It also includes specific questions on the operation and maintenance of wastewater

stabilization ponds and state regulations regarding the classification of wastewater

treatment plants and operator certification.

In addition, the Grade II examination includes questions on secondary unit processes

(e.g. trickling filters, activated sludge), sludge handling, evaluation of wastewater unit

processes as well as overall plant performance and basic supervision responsibilities.

The Grade II examination also contains mathematical questions. Examinees may be

asked to calculate a variety of problems including hydraulic or organic loading rate, SVI

index, removal efficiency (% removal), activated sludge F/M ratio, activated sludge

MCRT, pumping rate, sludge pumping rate, detention time, chlorine residual/demand,

flow velocity, volume or surface area, overflow rate and nitrification. The examinee

should be familiar with typical calculations related to the subject matter listed in

paragraph 1.

Examinees are given 2 ½ hours to complete the examination. The question format is as

follows:

50 True/False Questions

30 Multiple Choice Questions

10 Math Problems

1 point each

2 points each

4 points each

TOTAL POINTS 150

Passing Score: To pass, you must achieve:

(a) a minimum total score of 105 points (70 percent), AND

a score of at least 20 points (50 percent) on the ten Math Questions.

GRADE III

WWTP OPERATOR

EXAMINATION INFORMATION

The Grade III examination contains questions regarding the following subjects: basic

safety practices, hazards encountered during wastewater treatment plant operations,

sampling and simple analysis of wastewater constituents, and operation and

maintenance procedures in preliminary and primary treatment unit processes, anaerobic

sludge digestion and disinfection.

It also includes specific questions on the operation and maintenance of wastewater

stabilization ponds and state regulations regarding the classification of wastewater

treatment plants and operator certification.

Other questions may deal with secondary unit processes (e.g. trickling filters, activated

sludge), sludge handling, evaluation of wastewater unit processes as well as overall

plant performance and basic supervision.

In addition, the Grade III examination includes questions on process control, activated

sludge process modifications and tertiary treatment.

The Grade III examination also contains mathematical questions. Examinees may be

asked to calculate a variety of problems including efficiency and loading of solid

thickening processes, disinfectant usage, digester loading, pumping efficiency, standard

BOD test, hydraulic or organic loading rate, activated sludge wasting rate, MLVSS and

MLSS, sludge pumping rate, nitrogenous BOD calculation, F/M ratio and polymer

usage. The examinee should be familiar with typical calculations related to the subject

matter listed in paragraph 1.

Examinees are given 3 ½ hours to complete the examination. The question format is as

follows:

25 True/False Questions

@ 1 point each

@ 2 points each

97 TOTAL POINTS

20 Multiple Choice Questions

6 Multiple Choice Essay Questions

10 Multiple Choice Math Problems

Passing Score: To pass, you must achieve:

(a) a minimum total score of 68 points (70 percent) AND

(b) a score of at least 10 points (50 percent) on the Math Questions.

Rev. 2/2021

GRADE IV

WWTP OPERATOR

EXAMINATION INFORMATION

The Grade IV examination contains questions regarding the following subjects: safety

practices, hazards encountered during operations, sampling and analysis of wastewater

constituents, operation and maintenance procedures in preliminary, primary and

secondary treatment unit processes, anaerobic sludge digestion and disinfection.

It also includes operation and maintenance of wastewater stabilization ponds and state

regulations regarding the classification of wastewater treatment plants and operator

certification. Questions may deal with sludge handling and evaluation of wastewater unit

processes as well as overall plant performance.

In addition, the Grade IV examination includes questions on process control, activated

sludge process modifications and tertiary treatment, requirements and practices for

water reclamation and reuse, supervision/management responsibilities such as energy

management, safety program development, operator training and budget development

and control.

The Grade IV examination also contains mathematical questions. Examinees may be

asked to calculate problems including heat value/gas generation from an anaerobic

digester, BOD/nitrogenous BOD calculations, effects of process adjustments/changes,

polymer usage/dose, efficiency and loading of solids thickening processes, disinfection

options/dose/residual/cost, use/calculation of process control variables, hydraulic or

organic loading rates, pumping efficiency/cost, nitrification and effects of plant

operations and infiltration and inflow. The examinee should be familiar with typical

calculations related to the subject matter listed in paragraph 1.

Examinees are given 4 hours to complete the examination. The question format is as

follows:

25 Multiple Choice Questions

@ 2 points each

24 Multiple Choice Essay Questions @ 2 points each

15 Multiple Choice Math Problems

@ 2 points each

128 TOTAL POINTS

Passing Score: To pass, you must achieve:

(a) a minimum total score of 90 points (70 percent) AND

(b) a score of at least 15 points (50 percent) on the Math Questions.

Rev. 2/2021

GRADE V

WWTP OPERATOR

EXAMINATION INFORMATION

The Grade V examination contains questions regarding the following subjects: safety

practices, hazards encountered during operations, sampling and analysis of wastewater

constituents, operation and maintenance procedures in preliminary, primary and

secondary treatment unit processes, anaerobic sludge digestion and disinfection.

It also includes operation and maintenance of wastewater stabilization ponds and state

regulations regarding the classification of wastewater treatment plants and operator

certification. Questions may deal with sludge handling and evaluation of wastewater unit

processes as well as overall plant performance.

In addition, the Grade V examination includes questions on process control, activated

sludge process modifications and tertiary treatment, requirements and practices for

water reclamation and reuse, supervision/management responsibilities such as energy

management, safety program development, operator training and budget development

and control.

The Grade V examination contains some of the most complex mathematical questions

asked at Grades I-IV. Examinees may be asked to calculate problems including heat

value/gas generation from an anaerobic digester, BOD/nitrogenous BOD calculations,

effects of process adjustments/changes, polymer usage/dose, efficiency and loading of

solids thickening processes, disinfection options/dose/residual/cost, use/calculation of

process control variables, hydraulic or organic loading rates, pumping efficiency/cost,

nitrification and effects of plant operations and infiltration and inflow. The examinee

should be familiar with typical calculations related to the subject matter listed in

paragraph 1.

Examinees are given 4 hours to complete the examination. The question format is as

follows:

25 Multiple Choice Questions

@ 2 points each

29 Multiple Choice Essay Problems @ 2 points each

16 Multiple Choice Math Problems

@ 2 points each

140 TOTAL POINTS

Passing Score: To pass, you must achieve:

(a) a minimum total score of 98 points (70 percent) AND

(b) a score of at least 16 points (50 percent) on the Math Questions.

Rev. 2/2021

D. CCR Drinking Water Regs - TOC

California Regulations Related to Drinking Water

April 10, 2017

Sections amended, adopted, repealed, or not included in the previous version are highlighted in yellow. If the text in a

section, subsection, or paragraph is highlighted, it is new. If only the section/paragraph number is highlighted, it was

amended or repealed. Nonsubstantive revisions may not be shown. Please note that the water recycling criteria have

been removed from this document, but may still be viewed in the “Recycled Water-Related Regulations” document

here: http://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/Lawbook.shtml

TITLE 17 CODE OF REGULATIONS

DIVISION 1. STATE DEPARTMENT OF HEALTH SERVICES AND

STATE WATER RESOURCES CONTROL BOARD

CHAPTER 5. SANITATION (ENVIRONMENTAL)

SUBCHAPTER 1. ENGINEERING (SANITARY)

GROUP 4. DRINKING WATER SUPPLIES

Article 1. General

§7583. Definitions

§7584. Responsibility and scope of program

§7585. Evaluation of hazard.

§7586. User supervisor

Article 2. Protection of Water System

§7601. Approval of backflow preventers

§7602. Construction of backflow preventers

§7603. Location of backflow preventers

§7604. Type of protection required.

§7605. Testing and maintenance of backflow preventers

Article 5. Domestic Water Supply Reservoirs

§7625. Definitions

§7626. Application for Permit

§7627. Data to Accompany Application

§7629. Reservoirs for Which Permits May be Granted

TITLE 22 CODE OF REGULATIONS

DIVISION 4. ENVIRONMENTAL HEALTH

CHAPTER 1. INTRODUCTION

Article 1. Definitions

§60001. Department

§60002. State Board.

§60003. Director

Article 2. Monitoring and Reporting Requirements - Scope

§60098. Monitoring and Reporting Requirements

CHAPTER 2. REGULATIONS FOR THE IMPLEMENTATION OF

THE CALIFORNIA ENVIRONMENTAL QUALITY ACT

Article 1. General Requirements and Categorical Exemptions

§60100. General requirements

§60101. Specific Activities Within Categorical Exempt Classes.

CHAPTER 12. SAFE DRINKING WATER PROJECT FUNDING

(Repealed)

CHAPTER 13. OPERATOR CERTIFICATION

Article 1. Definitions

§63750.10. Accredited Academic Institution

§63750.15. Certificate

§63750.20. Certified Distribution Operator

§63750.25. Chief Operator

§63750.30. Comprehensive Operator Training Program

§63750.35. Contact Hour

§63750.40. Continuing Education Course.

§63750.45. Distribution Operator

§63750.50. Distribution System

§63750.55. GED

§63750.60. Interim Distribution Operator Certificate

§63750.65. Operator Experience

§63750.70. Shift Operator

§63750.75. Specialized Training.

§63750.85. Water treatment facility

Article 2. Operator Certification Grades

§63765. Water Treatment Facility Staff Certification Requirements

§63770. Distribution System Staff Certification Requirements

Article 3. Operator Examination Criteria and Applications

§63775. Eligibility Criteria for Taking a Water Treatment Operator Examination.

§63780. Eligibility Criteria for Taking a Distribution Operator Examination

§63785. Examination Application Content and Submittal

§63790. Filing Deadline and Requirement for Identification at Examination.

§63795. Examination Application Resubmittals and Reexaminations

Article 4. Operator Certification Criteria and Applications

§63800. Eligibility Criteria for Water Treatment Operator Certification

§63805. Eligibility Criteria for Distribution Operator Certification

§63810. Interim Certification of Distribution Operators

§63815. CNAWWA Distribution Operator Certification

§63820. Temporary Distribution Operator Certification.

§63825. Restricted Operator Certification.

§63830. Certification Application Content and Submittal

§63835. Certification Application Resubmittal.

Article 5. Certification Renewals, Delinquent Renewals and Fees

§63840. Certification Renewals.

§63845. Reinstatement

§63850. Fees

CHAPTER 14. WATER PERMITS

Article 1. Applications

§64001. Water Permit Application.

Article 3. State Small Water Systems

§64211. Permit Requirement

§64212. Bacteriological Quality Monitoring.

§64213. Chemical Quality Monitoring.

§64214. Service Connection Limitation.

§64215. Water Supply Requirements

§64216. Mutual Associations Prohibited.

§64217. Surface Water Treatment Requirement

Article 4. Local Primacy Delegation

§64251. Definitions

§64252. Primacy Delegation Application.

§64253. Local Primacy Agency Minimum Program Requirements

§64254. Permits

§64255. Surveillance

§64256. Sampling and Monitoring.

§64257. Reporting.

§64258. Enforcement

§64259. Program Management

§64260. Workplans

CHAPTER 14.5 FEES

Article 1. Public Water System Annual Fees

§64300. Definitions

§64305. Fee Schedule for Annual Fees

§64310. Reduction of Fees for Public Water Systems Serving Disadvantaged

Community.

§64315. Payment of Fees

CHAPTER 15. DOMESTIC WATER QUALITY AND MONITORING

REGULATIONS

Article 1. Definitions

§64400. Acute Risk.

§64400.05. Combined Distribution System

§64400.10. Community Water System

§64400.20. Compliance Cycle.

§64400.25. Compliance Period.

§64400.28. Confluent Growth.

§64400.29. Consecutive System

§64400.30. Customer

§64400.32. Detected.

§64400.34. Detection Limit for Purposes of Reporting (DLR)

§64400.36. Dual Sample Set

§64400.38. Enhanced Coagulation.

§64400.40. Enhanced Softening.

§64400.41. Finished Water

§64400.42. Fluoridation

§64400.45. GAC10.

§64400.46. GAC20.

§64400.47. Haloacetic Acids (Five) or HAA5.

§64400.50. Initial Compliance Period

§64400.60. Initial Finding.

§64400.65. IOC

§64400.66. Locational Running Annual Average or LRAA

§64400.67. Maximum Residual Disinfectant Level or MRDL

§64400.70. MCL

§64400.80. Nontransient-noncommunity Water System

§64400.90. Operational Evaluation Levels or OEL

§64401. Repeat Compliance Period

§64401.10. Repeat Sample

§64401.20. Replacement Sample

§64401.30. Routine Sample

§64401.40. Sanitary Survey.

§64401.50. Significant Rise in Bacterial Count

§64401.55. SOC

§64401.60. Standby Source

§64401.65. SUVA

§64401.70. System with a Single Service Connection.

§64401.71. Tier 1 Public Notice

§64401.75. Too Numerous to Count

§64401.80. Total Coliform-positive

§64401.82. Total Organic Carbon or TOC

§64401.85. Transient-noncommunity Water System

§64401.90. Treatment

§64401.92. Total Trihalomethanes or TTHM

§64401.95. VOC

§64402. Vulnerable System

§64402.10. Water Source

§64402.20. Water Supplier

§64402.30. Wholesale System

Article 2. General Requirements

§64412. Determination of Persons Served.

§64413.1. Classification of Water Treatment Facilities

§64413.3. Classification of Distribution Systems

§64413.5. Treatment Facility Staff Certification Requirements

§64413.7. Distribution System Staff Certification Requirements

§64414. Standby Sources

§64415. Laboratory and Personnel

§64416. Sampling Plan for all Monitoring Except Bacteriological.

ARTICLE 2.5. Point-of-Use Treatment

§64417. Definitions

§64418. General Provisions

§64418.1. Economic Feasibility of Centralized Treatment

§64418.2. POU Requirements

§64418.3. POU Treatment Strategy.

§64418.4. POU Operations and Maintenance (O&M) Program

§64418.5. POU Monitoring Program

§64418.6. Public Hearing and Acceptance

§64418.7. Recordkeeping, Reporting, and Compliance

ARTICLE 2.7. Point-of-Entry Treatment

§64419. Definitions

§64420.1. Economic Feasibility of Centralized Treatment

§64420.2. POE Requirements

§64420.3. POE Treatment Strategy.

§64420.4. POE Operations and Maintenance (O&M) Program

§64420.5. POE Monitoring Program

§64420.6. Public Hearing and Acceptance

§64420.7. Recordkeeping, Reporting, and Compliance

Article 3. Primary Standards--Bacteriological Quality

§64421. General Requirements

§64422. Routine Sample Siting Plan

§64423. Routine Sampling.

§64423.1. Sample Analysis and Reporting of Results

§64424. Repeat Sampling.

§64425. Sample Invalidation.

§64426. Significant Rise in Bacterial Count

§64426.1. Total Coliform Maximum Contaminant Level (MCL)

§64426.5. Variance from Total Coliform Maximum Contaminant Level

§64427. Sanitary Survey

Article 3.5. Ground Water Rule

§64430. Requirements

Article 4. Primary Standards--Inorganic Chemicals

§64431. Maximum Contaminant Levels--Inorganic Chemicals.

§64432. Monitoring and Compliance--Inorganic Chemicals.

§64432.1. Monitoring and Compliance--Nitrate and Nitrite

§64432.2. Monitoring and Compliance - Asbestos.

§64432.3. Monitoring and Compliance - Perchlorate

Article 4.1. Fluoridation

§64433. System Requirements and Exemptions

§64433.2. Optimal Fluoride Levels

§64433.3. Monitoring and Compliance--Fluoride Levels

§64433.5. Fluoridation System

§64433.7. Recordkeeping, Reporting, and Notification for Water Systems

Fluoridating

§64433.8. Fluoridation System Operations Contingency Plan.

§64434. Water System Priority Funding Schedule

Article 5. Radioactivity

§64442. MCLs and Monitoring - Gross Alpha Particle Activity, Radium-

226,Radium-228, and Uranium

§64443. MCLs and Monitoring - Beta Particle and Photon Radioactivity

Article 5.5. Primary Standards -- Organic Chemicals

§64444. Maximum Contaminant Levels – Organic Chemicals.

§64445. Initial sampling - organic chemicals.

§64445.1. Monitoring and Compliance – Organic Chemicals.

§64445.2. Sampling of Treated Water Sources.

Article 12. Best available technologies (BAT)

§64447. Best available technologies (BAT) – Microbiological Contaminants

§64447.2. Best available technologies (BAT) - inorganic chemicals.

§64447.3. Best Available Technologies (BAT) - Radionuclides

§64447.4. Best Available Technologies (BATs) - Organic Chemicals.

Article 14. Treatment Techniques

§64448. Treatment Technique Requirements

Article 16. Secondary Drinking Water Standards

§64449. Secondary Maximum Contaminant Levels and Compliance

§64449.2. Waivers for Secondary MCL Compliance

§64449.4. Use of Sources that Exceed a Secondary MCL and Do Not Have Waiver

§64449.5. Distribution System Physical Water Quality.

Article 18. Notification of Water Consumers and the State Board

§64463. General Public Notification Requirements

§64463.1. Tier 1 Public Notice

§64463.4. Tier 2 Public Notice

§64463.7. Tier 3 Public Notice

§64465. Public Notice Content and Format

§64466. Special Notice for Unregulated Contaminant Monitoring Results.

Article 19. Records, Reporting and Recordkeeping

§64469. Reporting Requirements

§64470. Recordkeeping.

Article 20. Consumer Confidence Report

§64481. Content of the Consumer Confidence Report

§64482. Required Additional Health Information.

§64483. Consumer Confidence Report Delivery and Recordkeeping.

CHAPTER 15.5 DISINFECTANT RESIDUALS, DISINFECTION

BYPRODUCTS, AND DISINFECTION BYPRODUCT

PRECURSORS

Article 1. General Requirements and Definitions

§64530. Applicability of this Chapter

§64531. Definitions Governing Terms Used in this Chapter

Article 2. Maximum Contaminant Levels for Disinfection Byproducts and

Maximum Residual Disinfectant Levels

§64533. Maximum Contaminant Levels for Disinfection Byproducts

Best Available Technology

§64533.5. Maximum Residual Disinfectant Levels

Article 3. Monitoring requirements

§64534. General Monitoring Requirements

§64534.2. Disinfection Byproducts Monitoring.

§64534.4. Disinfectant Residuals Monitoring.

§64534.6. Disinfection Byproduct Precursors Monitoring.

§64534.8. Monitoring Plans

Article 4. Compliance requirements

§64535. General Requirements for Determining Compliance.

§64535.2. Determining Disinfection Byproducts Compliance

§64535.4. Determining Disinfectant Residuals Compliance

Article 5. Treatment technique for control of disinfection byproduct

precursor(DBPP)

§64536. Alternative Compliance Criteria to the Enhanced Coagulation and

Enhanced Softening Performance Requirements

§64536.2. Enhanced Coagulation and Enhanced Softening Performance

Requirements.

§64536.4. Disinfection Byproduct Precursor Compliance Calculations

§64536.6. Disinfection Byproduct Precursors Public Notification Requirements.

Article 6. Reporting and recordkeeping requirements

§64537. General Reporting and Recordkeeping Requirements

§64537.2. Disinfection Byproducts Reporting.

§64537.4. Disinfectants Reporting.

§64537.6. Disinfection Byproduct Precursors and Enhanced Coagulation or

Enhanced Softening Reporting.

CHAPTER 16. CALIFORNIA WATERWORKS STANDARDS196

Article 1. Definitions

§64551.10. Distribution Reservoir

§64551.20. Distribution System

§64551.35. Peak Hour Demand (PHD)

§64551.40. Source Capacity.

§64551.60. User Service Line

§64551.70. Water Main.

Article 1.5. Waivers and Alternatives

§64551.100. Waivers and Alternatives

Article 2. Permit Requirements

§64552. Initial Permit for Public Water System

§64554. New and Existing Source Capacity.

§64556. Permit Amendments

§64558. Source Capacity Planning Study.

Article3. Water Sources

§64560. New Well Siting, Construction, and Permit Application.

§64560.5. Well Destruction.

§64561. Source Flow Meters

Article 4. Materials and Installation of Water Mains and Appurtenances

§64570. Materials and Installation.

§64572. Water Main Separation.

§64573. Minimum Water Main Size for Community Water Systems

§64575. Flushing.

§64576. Air-Release, Air Vacuum, and Combination Valves

§64577. Isolation Valves

§64578. Water Main Valve Construction.

Article 5. Disinfection Requirements

§64580. Disinfection of New or Repaired Mains

§64582. Disinfection of Reservoirs

§64583. Disinfection of Wells

Article 6. Distribution Reservoirs

§64585. Design and Construction.

Article 7. Additives

§64590. Direct Additives

§64591. Indirect Additives

§64593. Use of Uncertified Chemicals, Materials or Products

Article 8. Distribution System Operation

§64600. Water System Operations and Maintenance Plan.

§64602. Minimum Pressure

§64604. Preparation and Maintenance of Records

CHAPTER 17. SURFACE WATER TREATMENT

Article 1. General Requirements and Definitions

§64650. General Requirements

§64651.10. Approved Surface Water

§64651.12. Bag Filters

§64651.13. Bank Filtration.

§64651.15. Cartridge Filters

§64651.16. Coagulant Chemical

§64651.20. Coagulation

§64651.21. Comprehensive Performance Evaluation (CPE)

§64651.23. Conventional Filtration Treatment

§64651.26. Diatomaceous Earth Filtration.

§64651.30. Direct Filtration Treatment

§64651.32. Disinfectant Contact Time

§64651.33. Disinfection

§64651.34. Disinfection Profile

§64651.36. Engineering Report

§64651.38. Filter Profile

§64651.40. Filter-To-Waste.

§64651.43. Filtration.

§64651.46. Flocculation

§64651.48. Flowing Stream

§64651.50. Groundwater Under the Direct Influence of Surface Water

§64651.52. Lake/Reservoir

§64651.53. Legionella

§64651.54. Membrane Filtration

§64651.56. Multibarrier Treatment

§64651.60. NTU (Nephelometric Turbidity Unit)

§64651.61. Plant Intake

§64651.62. Presedimentation.

§64651.63. Pressure Filter.

§64651.66. Qualified Engineer

§64651.70. Residual Disinfectant Concentration

§64651.73. Sedimentation.

§64651.76. Slow Sand Filtration.

§64651.80. Supplier

§64651.83. Surface Water

§64651.86. Turbidity Level

§64651.88. Uncovered Finished Water Storage Facility.

§64651.90. Virus

§64651.91. Waterborne Microbial Disease Outbreak.

§64651.93. Watershed.

Article 2. Treatment Technique Requirements, Watershed Protection

Requirements, and Performance Standards

§64652. Treatment Technique Requirements and Compliance Options

§64652.5. Criteria for Avoiding Filtration.

§64653. Filtration.

§64653.5. Recycle Provisions

Article 3. Monitoring Requirements

§64654.8. Source, Raw, Settled, and Recycled Filter Backwash Monitoring.

§64655. Filtration Monitoring.

§64656. Disinfection Monitoring.

§64656.5. Disinfection Profiling and Benchmarking.

Article 4. Design Standards

§64658. New Treatment Plants

§64659. Reliability.

Article 5. Operation

§64660. Operating Criteria

§64661. Operations Plan.

§64662. Records

Article 6. Reporting

§64663. State Board Notification.

§64664. Monthly Report

§64664.2. Supplemental Reports

Article 7. Sanitary Surveys

§64665. Watershed Requirements.

§64665.5. Additional Requirements

Article 8. Public Notification

§64666. Consumer Notification.

CHAPTER 17.5. LEAD AND COPPER

Article 1. General Requirements and Definitions

§64670. General Requirements

§64671.05. Action Level

§64671.08. Action Level Exceedance

§64671.09. Corrosion Control Treatment or CCT

§64671.10. Corrosion Inhibitor.

§64671.15. Detection Limit for Purposes of Reporting or DLR

§64671.30. Large Water System

§64671.35. Lead Service Line

§64671.40. Medium-size Water System

§64671.55. Period.

§64671.65. Single-family Structure

§64671.70. Small Water System

§64671.75. Tap Sampling.

§64671.80. Water Quality Parameter or WQP

§64671.85. WQP Monitoring.

Article 2. Requirements According to System Size

§64673. Small and Medium-size Water System Requirements

§64674. Large Water System Requirements

Article 3. Monitoring for Lead and Copper

§64675. General Requirements for Tap Sampling for Lead and Copper

§64675.5. Tap Sampling Frequency.

§64676. Sample Site Selection.

§64677. Sample Collection Methods for Taps

§64677.5. Sample Invalidation.

§64678. Determination of Exceedances of Lead and Copper Action Levels

§64678.5. Monitoring Waivers for Small Systems

§64679. Supplemental Monitoring.

Article 4. Water Quality Parameter (WQP) Monitoring

§64680. General WQP Monitoring Requirements

§64681. Initial WQP Monitoring.

§64682. WQP Monitoring After CCT Installation

Article 5. Corrosion Control

§64683. Corrosion Control Study Procedure

§64684. CCT Installation and Operation.

Article 6. Source Water Requirements for Action Level Exceedances

64685. Source Water Monitoring and Treatment Designation.

§64686. Requirements Subsequent to the Department’s Designation

Article 7. Public Education Program for Lead Action Level Exceedances

§64687. Lead Public Education Program Content and Delivery.

Article 8. Lead Service Line Requirements for Action Level Exceedances

§64688. Lead Service Line Replacement

§64689. Lead Service Line Sampling.

Article 9. Reporting and Recordkeeping

§64690.10. Data Reporting.

§64690.80. Recordkeeping.

Addendum A: CA Ground Water Rule – A reference to text adopted pursuant to

Section 64430.

§141.21. Coliform sampling.

§141.28. Certified laboratories

§141.153. Content of the reports

Appendix A to Subpart O of Part 141 – Regulated Contaminants

§141.202. Tier 1 Public Notice – Form, manner, and frequency of notice

§141.202. Tier 2 Public Notice – Form, manner, and frequency of notice

Appendix A to Subpart Q of Part 141 – NPDWR Violations and Other Situations

Requiring Public Notice.

Appendix B to Subpart Q of Part 141 – Standard Health Effects Language for Public

Notification.

§141.400. General requirements and applicability

§141.401. Sanitary surveys for ground water systems.

§141.402. Ground water source microbial monitoring and analytical methods

§141.403. Treatment technique requirements for ground water systems

§141.404. Treatment technique violations for ground water systems

Addendum B: CA Long Term 2 Enhanced Surface Water Treatment Rule – A

reference to text adopted pursuant to Section 64650(f). [CFR § 141.74 not

shown.]

§ 141.211. Special notice for repeated failure to conduct monitoring of the source

water for Cryptosporidium and for failure to determine bin classification or mean

Cryptosporidium level

Appendix A to Subpart Q of Part 141—NPDWR Violations and Other Situations

Requiring Public Notice ¹

§ 141.700. General requirements

§ 141.701. Source water monitoring.

§ 141.702. Sampling schedules

§ 141.703. Sampling locations

§ 141.704. Analytical methods

§ 141.705. Approved laboratories

§ 141.706. Reporting source water monitoring results

§ 141.707. Grandfathering previously collected data.

§ 141.708. Requirements when making a significant change in disinfection practice.

§ 141.709. Developing the disinfection profile and benchmark.

§ 141.710. Bin classification for filtered systems

§ 141.711. Filtered system additional Cryptosporidium treatment requirements

§ 141.712. Unfiltered system Cryptosporidium treatment requirements.3

§ 141.713. Schedule for compliance with Cryptosporidium treatment requirements

§ 141.714. Requirements for uncovered finished water storage facilities

§ 141.715. Microbial toolbox options for meeting Cryptosporidium treatment

requirements.

§ 141.716. Source toolbox components

§ 141.717. Pre-filtration treatment toolbox components

§ 141.718. Treatment performance toolbox components

§ 141.719. Additional filtration toolbox components

§ 141.720. Inactivation toolbox components

§ 141.721. Reporting requirements

§ 141.722. Recordkeeping requirements

§ 141.723. Requirements to respond to significant deficiencies identified in sanitary

surveys performed by EPA

E. Water Treatment Facilities Classiﬁcation

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View Document - California Code of Regulations

California Code of Regulations

Home Table of Contents

§ 64413.1. Classification of Water Treatment Facilities.

22 CA ADC § 64413.1

Barclays Official California Code of Regulations

Barclays California Code of Regulations

Title 22. Social Security

Division 4. Environmental Health

Chapter 15. Domestic Water Quality and Monitoring Regulations

Article 2. General Requirements

22 CCR § 64413.1

§ 64413.1. Classification of Water Treatment Facilities.

Currentness

(a) Each water treatment facility shall be classified pursuant to Table 64413.1-A based on the calculation of total points for the facility

using the factors specified in subsection (b).

Table 64413.1-A. Water Treatment Facility Class Designations

Total Points

Less than 20

20 through 39

40 through 59

60 through 79

80 or more

Class

(b) The calculation of total points for each water treatment facility shall be the sum of the points derived in each of paragraphs (1)

through (13). If a treatment facility treats more than one source, the source with the highest average concentration of each

contaminant shall be used to determine the point value in paragraphs (2) through (5).

(1) For water source, the points are determined pursuant to Table 64413.1-B.

Table 64413.1-B. Points for Source Water Used by the Facility

Type of source water used by the facility

Points

Groundwater and/or purchased treated water meeting primary and secondary drinking water standards, as

defined in section 116275 of the Health and Safety Code

Water that includes any surface water or groundwater under the direct influence of surface water

(2) For influent microbiological water quality, points shall be determined by using the median of all total coliform analyses

completed in the previous 24 months pursuant to Table 64413.1-C:

Table 64413.1-C. Influent Water Microbiological Quality Points

Median Coliform Density Most Probable Number Index (MPN)

less than 1 per 100 mL

Points

1 through 100 per 100 mL

greater than 100 through 1,000 per 100 mL

greater than 1,000 through 10,000 per 100 mL

greater than 10,000 per 100 mL

(3) For facilities treating surface water or groundwater under the direct influence of surface water, points for influent water turbidity

shall be determined pursuant to Table 64413.1-D on the basis of the previous 24 months of data, except that if turbidity data is

missing for one or more of the months, the points given for turbidity shall be 5. The maximum influent turbidity sustained for at

least one hour according to an on-line turbidimeter shall be used unless such data is not available, in which case, the maximum

influent turbidity identified by grab sample shall be used. For facilities that have not been in operation for 24 months, the available

data shall be used. For facilities whose permit specifies measures to ensure that influent turbidity will not exceed a specified level,

the points corresponding to that level shall be assigned.

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Table 64413.1-D. Influent Water Turbidity Points

View Document - California Code of Regulations

Maximum Influent Turbidity Level Nephelometric Turbidity Units (NTU)

Points

Less than 15

15 through 100

Greater than 100

(4) The points for influent water perchlorate, nitrate, or nitrite levels shall be determined by an average of the three most recent

sample results, pursuant to Table 64413.1-E.

Table 64413.1-E. Influent Water Perchlorate, Nitrate, and Nitrite Points

Perchlorate, Nitrate, and Nitrite Data Average

Points

Less than or equal to the maximum contaminant level (MCL), as specified in Table 64431-A

For each contaminant greater than its MCL

(5) The points for other influent water contaminants with primary MCLs shall be a sum of the points for each of the inorganic

contaminants (Table 64431-A), organic contaminants (Table 64444-A) and radionuclides (Tables 64442 and 64443). The points for

each contaminant shall be based on an average of the three most recent sample results, pursuant to Table 64413.1-F. If

monitoring for a contaminant has been waived pursuant to sections 64432(m) or (n), 64432.2(c), or 64445(d), the points shall be

zero for that contaminant.

Table 64413.1-F. Influent Water Chemical and Radiological Contaminant Points

Contaminant Data Average

Less than or equal to the MCL

Greater than the MCL

Points

5 Times the MCL or greater

(6) The total points for surface water filtration treatment shall be the sum of the points of those treatment processes utilized by the

facility for compliance with section 64652, pursuant to Table 64413.1-G.

Table 64413.1-G. Points for Surface Water Filtration Treatment

Treatment

Points

Conventional, direct, or inline

Diatomaceous earth

Slow sand, membrane, cartridge, or bag filter

Backwash recycled as part of process

(7) The points for each treatment process utilized by the facility and not included in paragraph (6) that is used to reduce the

concentration of one or more contaminants for which a primary MCL exists, pursuant to Table 64431-A, Table 64444-A, and Tables

64442 and 64443, shall be 10. Blending shall only be counted as a treatment process if one of the blended sources exceeds a

primary MCL.

(8) The points for each treatment process not included in paragraphs (6), or (7) that is used to reduce the concentration of one or

more contaminants for which a secondary MCL exists, pursuant to Tables 64449-A and 64449-B, shall be 3. Blending shall only be

counted as a treatment process if one of the blended sources exceeds a secondary MCL.

(9) The points for each treatment process not included in paragraphs (6), (7), or (8) that is used for corrosion control or fluoridation

shall be 3.

(10) The total points for disinfection treatment shall be the sum of the points for those treatment processes utilized by the facility for

compliance with section 64654(a), pursuant to Table 64413.1-H.

Table 64413.1-H. Points for Disinfection Treatment

Treatment Process

Ozone

Points

Chlorine and/or chloramine

Chlorine dioxide

Ultra violet (UV)

(11) The points for disinfection/oxidation treatment not included in paragraphs (6), (7), (8), or (10) shall be a sum of the points for

all the treatment processes used at the facility pursuant to Table 64413.1-I.

Table 64413.1-I. Points for Disinfection/Oxidation Treatment without Inactivation Credit

Treatment Process

Points

Ozone

https://govt.westlaw.com/calregs/Document/I779854F85B6111EC9451000D3A7C4BC3?viewType=FullText&originationContext=documenttoc&transitio… 2/3

F. SDS Content - OSHA Guidance

Occupational Safety and Health Administration

Hazard Communication Standard: Safety Data

Sheets

The Hazard Communication Standard (HCS) (29 CFR 1910.1200(g)), revised in 2012, requires that the

chemical manufacturer, distributor, or importer provide Safety Data Sheets (SDSs) (formerly MSDSs or

Material Safety Data Sheets) for each hazardous chemical to downstream users to communicate information

on these hazards. The information contained in the SDS is largely the same as the MSDS, except now the

SDSs are required to be presented in a consistent user-friendly, 16-section format. This brief provides

guidance to help workers who handle hazardous chemicals to become familiar with the format and understand

the contents of the SDSs.

The SDS includes information such as the properties of each chemical; the physical, health, and environmental

health hazards; protective measures; and safety precautions for handling, storing, and transporting the

chemical. The information contained in the SDS must be in English (although it may be in other languages as

well). In addition, OSHA requires that SDS preparers provide specific minimum information as detailed in

Appendix D of 29 CFR 1910.1200. The SDS preparers may also include additional information in various

section(s).

Sections 1 through 8 contain general information about the chemical, identification, hazards, composition, safe

handling practices, and emergency control measures (e.g., fire fighting). This information should be helpful to

those that need to get the information quickly. Sections 9 through 11 and 16 contain other technical and

scientific information, such as physical and chemical properties, stability and reactivity information,

toxicological information, exposure control information, and other information including the date of

preparation or last revision. The SDS must also state that no applicable information was found when the

preparer does not find relevant information for any required element.

The SDS must also contain Sections 12 through 15, to be consistent with the UN Globally Harmonized System

of Classification and Labeling of Chemicals (GHS), but OSHA will not enforce the content of these sections

because they concern matters handled by other agencies.

A description of all 16 sections of the SDS, along with their contents, is presented below:

Section 1: Identification

This section identifies the chemical on the SDS as well as the recommended uses. It also provides the

essential contact information of the supplier. The required information consists of:

▪

Product identifier used on the label and any other common names or synonyms by which the substance is

known.

Name, address, phone number of the manufacturer, importer, or other responsible party, and emergency

phone number.

Recommended use of the chemical (e.g., a brief description of what it actually does, such as flame

retardant) and any restrictions on use (including recommendations given by the supplier).

Section 2: Hazard(s) Identification

This section identifies the hazards of the chemical presented on the SDS and the appropriate warning

information associated with those hazards. The required information consists of:

▪

The hazard classification of the chemical (e.g., flammable liquid, category ).

Signal word.

Hazard statement(s).

Pictograms (the pictograms or hazard symbols may be presented as graphical reproductions of the

symbols in black and white or be a description of the name of the symbol (e.g., skull and crossbones,

flame).

▪

Precautionary statement(s).

Description of any hazards not otherwise classified.

For a mixture that contains an ingredient(s) with unknown toxicity, a statement describing how much

(percentage) of the mixture consists of ingredient(s) with unknown acute toxicity. Please note that this is

a total percentage of the mixture and not tied to the individual ingredient(s).

Section 3: Composition/Information on Ingredients

This section identifies the ingredient(s) contained in the product indicated on the SDS, including impurities and

stabilizing additives. This section includes information on substances, mixtures, and all chemicals where a

trade secret is claimed. The required information consists of:

Substances

▪

Chemical name.

Common name and synonyms.

Chemical Abstracts Service (CAS) number and other unique identifiers.

Impurities and stabilizing additives, which are themselves classified and which contribute to the

classification of the chemical.

Mixtures

▪

Same information required for substances.

The chemical name and concentration (i.e., exact percentage) of all ingredients which are classified as

health hazards and are:

Present above their cut-off/concentration limits or

Present a health risk below the cut-off/concentration limits.

▪

The concentration (exact percentages) of each ingredient must be specified except concentration ranges

may be used in the following situations:

A trade secret claim is made,

There is batch-to-batch variation, or

The SDS is used for a group of substantially similar mixtures.

Chemicals where a trade secret is claimed A statement that the specific chemical identity and/or exact

percentage (concentration) of composition has been withheld as a trade secret is required.

Section 4: First-Aid Measures

This section describes the initial care that should be given by untrained responders to an individual who has

been exposed to the chemical. The required information consists of:

▪

Necessary first-aid instructions by relevant routes of exposure (inhalation, skin and eye contact, and

ingestion).

▪

Description of the most important symptoms or effects, and any symptoms that are acute or delayed.

Recommendations for immediate medical care and special treatment needed, when necessary.

Section 5: Fire-Fighting Measures

This section provides recommendations for fighting a fire caused by the chemical. The required information

consists of:

▪

Recommendations of suitable extinguishing equipment, and information about extinguishing equipment

that is not appropriate for a particular situation.

Advice on specific hazards that develop from the chemical during the fire, such as any hazardous

combustion products created when the chemical burns.

Recommendations on special protective equipment or precautions for firefighters.

Section 6: Accidental Release Measures

This section provides recommendations on the appropriate response to spills, leaks, or releases, including

containment and cleanup practices to prevent or minimize exposure to people, properties, or the environment.

It may also include recommendations distinguishing between responses for large and small spills where the

spill volume has a significant impact on the hazard. The required information may consist of recommendations

for:

▪

Use of personal precautions (such as removal of ignition sources or providing sufficient ventilation) and

protective equipment to prevent the contamination of skin, eyes, and clothing.

Emergency procedures, including instructions for evacuations, consulting experts when needed, and

appropriate protective clothing.

▪

Methods and materials used for containment (e.g., covering the drains and capping procedures).

Cleanup procedures (e.g., appropriate techniques for neutralization, decontamination, cleaning or

vacuuming; adsorbent materials; and/or equipment required for containment/clean up)

Section 7: Handling and Storage

This section provides guidance on the safe handling practices and conditions for safe storage of chemicals.

The required information consists of:

▪

Precautions for safe handling, including recommendations for handling incompatible chemicals, minimizing

the release of the chemical into the environment, and providing advice on general hygiene practices (e.g.,

eating, drinking, and smoking in work areas is prohibited).

▪

Recommendations on the conditions for safe storage, including any incompatibilities. Provide advice on

specific storage requirements (e.g., ventilation requirements)

Section 8: Exposure Controls/Personal Protection

This section indicates the exposure limits, engineering controls, and personal protective measures that can be

used to minimize worker exposure. The required information consists of:

▪

OSHA Permissible Exposure Limits (PELs), American Conference of Governmental Industrial Hygienists

(ACGIH) Threshold Limit Values (TLVs), and any other exposure limit used or recommended by the

chemical manufacturer, importer, or employer preparing the safety data sheet, where available.

Appropriate engineering controls (e.g., use local exhaust ventilation, or use only in an enclosed system).

Recommendations for personal protective measures to prevent illness or injury from exposure to

chemicals, such as personal protective equipment (PPE) (e.g., appropriate types of eye, face, skin or

respiratory protection needed based on hazards and potential exposure).

▪

Any special requirements for PPE, protective clothing or respirators (e.g., type of glove material, such as

PVC or nitrile rubber gloves; and breakthrough time of the glove material).

Section 9: Physical and Chemical Properties

This section identifies physical and chemical properties associated with the substance or mixture. The

minimum required information consists of:

▪

Appearance (physical state, color, etc.);

Upper/lower flammability or explosive limits;

Odor;

Vapor pressure;

Odor threshold;

Vapor density;

pH;

Relative density;

Melting point/freezing point;

Solubility(ies);

Initial boiling point and boiling range;

Flash point;

Evaporation rate;

Flammability (solid, gas);

Partition coefficient: n-octanol/water;

Auto-ignition temperature;

Decomposition temperature; and

Viscosity.

The SDS may not contain every item on the above list because information may not be relevant or is not

available. When this occurs, a notation to that effect must be made for that chemical property. Manufacturers

may also add other relevant properties, such as the dust deflagration index (Kst) for combustible dust, used to

evaluate a dust's explosive potential

Section 10: Stability and Reactivity

This section describes the reactivity hazards of the chemical and the chemical stability information. This

section is broken into three parts: reactivity, chemical stability, and other. The required information consists

of:

Reactivity

▪

Description of the specific test data for the chemical(s). This data can be for a class or family of the

chemical if such data adequately represent the anticipated hazard of the chemical(s), where available.

Chemical stability

▪

Indication of whether the chemical is stable or unstable under normal ambient temperature and conditions

while in storage and being handled.

▪

Description of any stabilizers that may be needed to maintain chemical stability.

Indication of any safety issues that may arise should the product change in physical appearance.

Other

▪

Indication of the possibility of hazardous reactions, including a statement whether the chemical will react

or polymerize, which could release excess pressure or heat, or create other hazardous conditions. Also, a

description of the conditions under which hazardous reactions may occur.

▪

List of all conditions that should be avoided (e.g., static discharge, shock, vibrations, or environmental

conditions that may lead to hazardous conditions).

List of all classes of incompatible materials (e.g., classes of chemicals or specific substances) with which

the chemical could react to produce a hazardous situation.

List of any known or anticipated hazardous decomposition products that could be produced because of

use, storage, or heating. (Hazardous combustion products should also be included in Section 5 (Fire-

Fighting Measures) of the SDS.)

Section 11: Toxicological Information

This section identifies toxicological and health effects information or indicates that such data are not available.

The required information consists of:

▪

Information on the likely routes of exposure (inhalation, ingestion, skin and eye contact). The SDS should

indicate if the information is unknown.

▪

Description of the delayed, immediate, or chronic effects from short- and long-term exposure.

The numerical measures of toxicity (e.g., acute toxicity estimates such as the LD50 (median lethal dose))

- the estimated amount [of a substance] expected to kill 50% of test animals in a single dose.

Description of the symptoms. This description includes the symptoms associated with exposure to the

chemical including symptoms from the lowest to the most severe exposure.

▪

Indication of whether the chemical is listed in the National Toxicology Program (NTP) Report on

Carcinogens (latest edition) or has been found to be a potential carcinogen in the International Agency for

Research on Cancer (IARC) Monographs (latest editions) or found to be a potential carcinogen by OSHA

Section 12: Ecological Information (non-mandatory)

This section provides information to evaluate the environmental impact of the chemical(s) if it were released

to the environment. The information may include:

▪

Data from toxicity tests performed on aquatic and/or terrestrial organisms, where available (e.g., acute or

chronic aquatic toxicity data for fish, algae, crustaceans, and other plants; toxicity data on birds, bees,

plants).

▪

Whether there is a potential for the chemical to persist and degrade in the environment either through

biodegradation or other processes, such as oxidation or hydrolysis.

Results of tests of bioaccumulation potential, making reference to the octanol-water partition coefficient

(Kow) and the bioconcentration factor (BCF), where available.

The potential for a substance to move from the soil to the groundwater (indicate results from adsorption

studies or leaching studies).

Other adverse effects (e.g., environmental fate, ozone layer depletion potential, photochemical ozone

creation potential, endocrine disrupting potential, and/or global warming potential).

Section 13: Disposal Considerations (non-mandatory)

This section provides guidance on proper disposal practices, recycling or reclamation of the chemical(s) or its

container, and safe handling practices. To minimize exposure, this section should also refer the reader to

Section 8 (Exposure Controls/Personal Protection) of the SDS. The information may include:

▪

Description of appropriate disposal containers to use.

Recommendations of appropriate disposal methods to employ.

Description of the physical and chemical properties that may affect disposal activities.

Language discouraging sewage disposal.

Any special precautions for landfills or incineration activities

Section 14: Transport Information (non-mandatory)

This section provides guidance on classification information for shipping and transporting of hazardous

chemical(s) by road, air, rail, or sea. The information may include:

▪

UN number (i.e., four-figure identification number of the substance) .

UN proper shipping name .

Transport hazard class(es) .

Packing group number, if applicable, based on the degree of hazard .

Environmental hazards (e.g., identify if it is a marine pollutant according to the International Maritime

Dangerous Goods Code (IMDG Code)).

▪

Guidance on transport in bulk (according to Annex II of MARPOL 73/78 and the International Code for

the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (International Bulk

Chemical Code (IBC Code)).

Any special precautions which an employee should be aware of or needs to comply with, in connection

with transport or conveyance either within or outside their premises (indicate when information is not

available).

Section 15: Regulatory Information (non-mandatory)

This section identifies the safety, health, and environmental regulations specific for the product that is not

indicated anywhere else on the SDS. The information may include:

▪

Any national and/or regional regulatory information of the chemical or mixtures (including any OSHA,

Department of Transportation, Environmental Protection Agency, or Consumer Product Safety Commission

regulations)

Section 16: Other Information

This section indicates when the SDS was prepared or when the last known revision was made. The SDS may

also state where the changes have been made to the previous version. You may wish to contact the supplier

for an explanation of the changes. Other useful information also may be included here.

Employer Responsibilities

Employers must ensure that the SDSs are readily accessible to employees for all hazardous chemicals in their

workplace. This may be done in many ways. For example, employers may keep the SDSs in a binder or on

computers as long as the employees have immediate access to the information without leaving their work

area when needed and a back-up is available for rapid access to the SDS in the case of a power outage or

other emergency. Furthermore, employers may want to designate a person(s) responsible for obtaining and

maintaining the SDSs. If the employer does not have an SDS, the employer or designated person(s) should

contact the manufacturer to obtain one.

G. Sample SDS

SAFETY DATA SHEET

Ammonia

Section 1. Identification

GHS product identifier

: Ammonia

Chemical name

: ammonia

Other means of

identification

: ammonia; anhydrous ammonia

Product type

Product use

: Gas.

: Synthetic/Analytical chemistry.

Synonym

SDS #

: ammonia; anhydrous ammonia

: 001003

Supplier's details

: Airgas USA, LLC and its affiliates

259 North Radnor-Chester Road

Suite 100

Radnor, PA 19087-5283

1-610-687-5253

24-hour telephone

1-866-734-3438

Section 2. Hazards identification

OSHA/HCS status

: This material is considered hazardous by the OSHA Hazard Communication Standard

(29 CFR 1910.1200).

Classification of the

substance or mixture

: FLAMMABLE GASES - Category 2

GASES UNDER PRESSURE - Liquefied gas

ACUTE TOXICITY (inhalation) - Category 4

SKIN CORROSION - Category 1

SERIOUS EYE DAMAGE - Category 1

AQUATIC HAZARD (ACUTE) - Category 1

GHS label elements

Hazard pictograms

Signal word

: Danger

Hazard statements

: Flammable gas.

May form explosive mixtures with air.

Contains gas under pressure; may explode if heated.

May displace oxygen and cause rapid suffocation.

Harmful if inhaled.

Causes severe skin burns and eye damage.

Very toxic to aquatic life.

Precautionary statements

General

: Read and follow all Safety Data Sheets (SDS’S) before use. Close valve after each use

and when empty. Use equipment rated for cylinder pressure. Do not open valve until

connected to equipment prepared for use. Use a back flow preventative device in the

piping. Use only equipment of compatible materials of construction. Always keep

container in upright position. Approach suspected leak area with caution.

Prevention

: Wear protective gloves. Wear eye or face protection. Wear protective clothing. Keep

away from heat, hot surfaces, sparks, open flames and other ignition sources. No

smoking. Use only outdoors or in a well-ventilated area. Avoid release to the

environment. Avoid breathing gas. Wash hands thoroughly after handling.

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

1/12

Ammonia

Section 2. Hazards identification

Response

: Collect spillage. IF INHALED: Remove person to fresh air and keep comfortable for

breathing. Immediately call a POISON CENTER or physician. IF SWALLOWED:

Immediately call a POISON CENTER or physician. Rinse mouth. Do NOT induce

vomiting. IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse

skin with water or shower. Wash contaminated clothing before reuse. Immediately call

a POISON CENTER or physician. IF IN EYES: Rinse cautiously with water for several

minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Immediately call a POISON CENTER or physician. Leaking gas fire: Do not extinguish,

unless leak can be stopped safely. Eliminate all ignition sources if safe to do so.

Storage

: Store locked up. Protect from sunlight. Store in a well-ventilated place.

Disposal

: Dispose of contents and container in accordance with all local, regional, national and

international regulations.

Hazards not otherwise

classified

: In addition to any other important health or physical hazards, this product may displace

oxygen and cause rapid suffocation.

Section 3. Composition/information on ingredients

Substance/mixture

: Substance

Chemical name

: ammonia

Other means of

identification

: ammonia; anhydrous ammonia

Product code

: 001003

CAS number/other identifiers

CAS number

: 7664-41-7

Ingredient name

CAS number

ammonia

100

7664-41-7

Any concentration shown as a range is to protect confidentiality or is due to batch variation.

There are no additional ingredients present which, within the current knowledge of the supplier and in the

concentrations applicable, are classified as hazardous to health or the environment and hence require reporting

in this section.

Occupational exposure limits, if available, are listed in Section 8.

Section 4. First aid measures

Description of necessary first aid measures

Eye contact

: Get medical attention immediately. Call a poison center or physician. Immediately flush

eyes with plenty of water, occasionally lifting the upper and lower eyelids. Check for and

remove any contact lenses. Continue to rinse for at least 10 minutes. Chemical burns

must be treated promptly by a physician.

Inhalation

: Get medical attention immediately. Call a poison center or physician. Remove victim to

fresh air and keep at rest in a position comfortable for breathing. If it is suspected that

fumes are still present, the rescuer should wear an appropriate mask or self-contained

breathing apparatus. If not breathing, if breathing is irregular or if respiratory arrest

occurs, provide artificial respiration or oxygen by trained personnel. It may be

dangerous to the person providing aid to give mouth-to-mouth resuscitation. If

unconscious, place in recovery position and get medical attention immediately. Maintain

an open airway. Loosen tight clothing such as a collar, tie, belt or waistband. In case of

inhalation of decomposition products in a fire, symptoms may be delayed. The exposed

person may need to be kept under medical surveillance for 48 hours.

Skin contact

: Get medical attention immediately. Call a poison center or physician. Flush

contaminated skin with plenty of water. Remove contaminated clothing and shoes. To

avoid the risk of static discharges and gas ignition, soak contaminated clothing

thoroughly with water before removing it. Continue to rinse for at least 10 minutes.

Chemical burns must be treated promptly by a physician. Wash clothing before reuse.

Clean shoes thoroughly before reuse.

Ingestion

: As this product is a gas, refer to the inhalation section.

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

2/12

Ammonia

Section 4. First aid measures

Most important symptoms/effects, acute and delayed

Potential acute health effects

Eye contact

Inhalation

Skin contact

Frostbite

: Causes serious eye damage.

: Harmful if inhaled.

: Causes severe burns.

: Try to warm up the frozen tissues and seek medical attention.

: As this product is a gas, refer to the inhalation section.

Ingestion

Over-exposure signs/symptoms

Eye contact

Inhalation

: Adverse symptoms may include the following:, pain, watering, redness

: No specific data.

Skin contact

: Adverse symptoms may include the following:, pain or irritation, redness, blistering may

occur

Ingestion

: Adverse symptoms may include the following:, stomach pains

Indication of immediate medical attention and special treatment needed, if necessary

Notes to physician

: In case of inhalation of decomposition products in a fire, symptoms may be delayed.

The exposed person may need to be kept under medical surveillance for 48 hours.

Specific treatments

: No specific treatment.

Protection of first-aiders

: No action shall be taken involving any personal risk or without suitable training. If it is

suspected that fumes are still present, the rescuer should wear an appropriate mask or

self-contained breathing apparatus. It may be dangerous to the person providing aid to

give mouth-to-mouth resuscitation. Wash contaminated clothing thoroughly with water

before removing it, or wear gloves.

See toxicological information (Section 11)

Section 5. Fire-fighting measures

Extinguishing media

Suitable extinguishing

media

: Use an extinguishing agent suitable for the surrounding fire.

Unsuitable extinguishing

media

: None known.

Specific hazards arising

from the chemical

: Contains gas under pressure. Flammable gas. In a fire or if heated, a pressure

increase will occur and the container may burst, with the risk of a subsequent explosion.

This material is very toxic to aquatic life. Fire water contaminated with this material

must be contained and prevented from being discharged to any waterway, sewer or

drain.

Hazardous thermal

: Decomposition products may include the following materials:

nitrogen oxides

decomposition products

Special protective actions

for fire-fighters

: Promptly isolate the scene by removing all persons from the vicinity of the incident if

there is a fire. No action shall be taken involving any personal risk or without suitable

training. Contact supplier immediately for specialist advice. Move containers from fire

area if this can be done without risk. Use water spray to keep fire-exposed containers

cool. If involved in fire, shut off flow immediately if it can be done without risk. If this is

impossible, withdraw from area and allow fire to burn. Fight fire from protected location

or maximum possible distance. Eliminate all ignition sources if safe to do so.

Special protective

: Fire-fighters should wear appropriate protective equipment and self-contained breathing

apparatus (SCBA) with a full face-piece operated in positive pressure mode.

equipment for fire-fighters

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

3/12

Ammonia

Section 6. Accidental release measures

Personal precautions, protective equipment and emergency procedures

For non-emergency

personnel

: Accidental releases pose a serious fire or explosion hazard. No action shall be taken

involving any personal risk or without suitable training. Evacuate surrounding areas.

Keep unnecessary and unprotected personnel from entering. Shut off all ignition

sources. No flares, smoking or flames in hazard area. Do not breathe gas. Provide

adequate ventilation. Wear appropriate respirator when ventilation is inadequate. Put

on appropriate personal protective equipment.

For emergency responders : If specialized clothing is required to deal with the spillage, take note of any information in

Section 8 on suitable and unsuitable materials. See also the information in "For non-

emergency personnel".

Environmental precautions : Ensure emergency procedures to deal with accidental gas releases are in place to avoid

contamination of the environment. Inform the relevant authorities if the product has

caused environmental pollution (sewers, waterways, soil or air). Water polluting

material. May be harmful to the environment if released in large quantities. Collect

spillage.

Methods and materials for containment and cleaning up

Small spill

: Immediately contact emergency personnel. Stop leak if without risk. Use spark-proof

tools and explosion-proof equipment.

Large spill

: Immediately contact emergency personnel. Stop leak if without risk. Use spark-proof

tools and explosion-proof equipment. Note: see Section 1 for emergency contact

information and Section 13 for waste disposal.

Section 7. Handling and storage

Precautions for safe handling

Protective measures

: Put on appropriate personal protective equipment (see Section 8). Contains gas under

pressure. Do not get in eyes or on skin or clothing. Do not breathe gas. Avoid release

to the environment. Use only with adequate ventilation. Wear appropriate respirator

when ventilation is inadequate. Do not enter storage areas and confined spaces unless

adequately ventilated. Store and use away from heat, sparks, open flame or any other

ignition source. Empty containers retain product residue and can be hazardous. Do not

puncture or incinerate container. Use equipment rated for cylinder pressure. Close

valve after each use and when empty. Protect cylinders from physical damage; do not

drag, roll, slide, or drop. Use a suitable hand truck for cylinder movement.

Advice on general

occupational hygiene

: Eating, drinking and smoking should be prohibited in areas where this material is

handled, stored and processed. Workers should wash hands and face before eating,

drinking and smoking. Remove contaminated clothing and protective equipment before

entering eating areas. See also Section 8 for additional information on hygiene

measures.

Conditions for safe storage, : Store in accordance with local regulations. Store in a segregated and approved area.

Store away from direct sunlight in a dry, cool and well-ventilated area, away from

incompatible materials (see Section 10). Store locked up. Eliminate all ignition sources.

Keep container tightly closed and sealed until ready for use. Cylinders should be stored

upright, with valve protection cap in place, and firmly secured to prevent falling or being

knocked over. Cylinder temperatures should not exceed 52 °C (125 °F).

including any

incompatibilities

Refer to ANSI/CGA G-2.1, Section 5.13 for electrical classification of anhydrous

ammonia storage and handling areas. Where anhydrous ammonia is stored indoors,

use electrical (ventilating, lighting and material handling) equipment with the appropriate

electrical classification rating and use only non-sparking tools.

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

4/12

Ammonia

Section 8. Exposure controls/personal protection

Control parameters

Occupational exposure limits

Ingredient name

Exposure limits

ammonia

California PEL for Chemical Contaminants (

Table AC-1) (United States).

PEL: 25 ppm 8 hours.

STEL: 35 ppm 15 minutes.

ACGIH TLV (United States, 3/2017).

TWA: 25 ppm 8 hours.

TWA: 17 mg/m³ 8 hours.

STEL: 35 ppm 15 minutes.

STEL: 24 mg/m³ 15 minutes.

OSHA PEL 1989 (United States, 3/1989).

STEL: 35 ppm 15 minutes.

STEL: 27 mg/m³ 15 minutes.

NIOSH REL (United States, 10/2016).

TWA: 25 ppm 10 hours.

TWA: 18 mg/m³ 10 hours.

STEL: 35 ppm 15 minutes.

STEL: 27 mg/m³ 15 minutes.

OSHA PEL (United States, 6/2016).

TWA: 50 ppm 8 hours.

TWA: 35 mg/m³ 8 hours.

Appropriate engineering

controls

: Use only with adequate ventilation. Use process enclosures, local exhaust ventilation or

other engineering controls to keep worker exposure to airborne contaminants below any

recommended or statutory limits. The engineering controls also need to keep gas,

vapor or dust concentrations below any lower explosive limits. Use explosion-proof

ventilation equipment.

Environmental exposure

controls

: Emissions from ventilation or work process equipment should be checked to ensure

they comply with the requirements of environmental protection legislation. In some

cases, fume scrubbers, filters or engineering modifications to the process equipment

will be necessary to reduce emissions to acceptable levels.

Individual protection measures

Hygiene measures

: Wash hands, forearms and face thoroughly after handling chemical products, before

eating, smoking and using the lavatory and at the end of the working period.

Appropriate techniques should be used to remove potentially contaminated clothing.

Wash contaminated clothing before reusing. Ensure that eyewash stations and safety

showers are close to the workstation location.

Eye/face protection

: Safety eyewear complying with an approved standard should be used when a risk

assessment indicates this is necessary to avoid exposure to liquid splashes, mists,

gases or dusts. If contact is possible, the following protection should be worn, unless

the assessment indicates a higher degree of protection: chemical splash goggles and/

or face shield. If inhalation hazards exist, a full-face respirator may be required instead.

Skin protection

Hand protection

: Chemical-resistant, impervious gloves complying with an approved standard should be

worn at all times when handling chemical products if a risk assessment indicates this is

necessary. Considering the parameters specified by the glove manufacturer, check

during use that the gloves are still retaining their protective properties. It should be

noted that the time to breakthrough for any glove material may be different for different

glove manufacturers. In the case of mixtures, consisting of several substances, the

protection time of the gloves cannot be accurately estimated.

Body protection

: Personal protective equipment for the body should be selected based on the task being

performed and the risks involved and should be approved by a specialist before

handling this product. When there is a risk of ignition from static electricity, wear anti-

static protective clothing. For the greatest protection from static discharges, clothing

should include anti-static overalls, boots and gloves.

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

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Section 8. Exposure controls/personal protection

Other skin protection

: Appropriate footwear and any additional skin protection measures should be selected

based on the task being performed and the risks involved and should be approved by a

specialist before handling this product.

Respiratory protection

: Based on the hazard and potential for exposure, select a respirator that meets the

appropriate standard or certification. Respirators must be used according to a

respiratory protection program to ensure proper fitting, training, and other important

aspects of use. Respirator selection must be based on known or anticipated exposure

levels, the hazards of the product and the safe working limits of the selected respirator.

Section 9. Physical and chemical properties

Appearance

Physical state

Color

: Gas. [Compressed gas.]

: Colorless.

Odor

: Pungent.

Not available.

Approx. 11.6

Odor threshold

Melting point

Boiling point

Critical temperature

Flash point

: -77.7°C (-107.9°F)

: -33°C (-27.4°F)

: 132.85°C (271.1°F)

: Not available.

Evaporation rate

Flammability (solid, gas)

: Not available.

: Extremely flammable in the presence of the following materials or conditions: oxidizing

materials.

Lower and upper explosive : Lower: 16%

Upper: 25%

(flammable) limits

Vapor pressure

Vapor density

: 114.1 (psig)

0.59 (Air = 1)

Specific Volume (ft ³/lb)

Gas Density (lb/ft ³)

Relative density

Solubility

: 20.79

: 0.0481 (32°C / 89.6 to °F)

: SPECIFIC GRAVITY (AIR=1): @ 70°F (21.1°C) = 0.59

: Soluble in water. Soluble in alcohol and ether.

: 540 g/l

Solubility in water

Partition coefficient: n-

octanol/water

: Not available.

Auto-ignition temperature

: 651°C (1203.8°F)

Decomposition temperature : Not available.

Viscosity

: Not applicable.

: Not available.

: 17.03 g/mole

Flow time (ISO 2431)

Molecular weight

Aerosol product

Heat of combustion

: -18589392 J/kg

Section 10. Stability and reactivity

Reactivity

: No specific test data related to reactivity available for this product or its ingredients.

Chemical stability

: The product is stable.

Possibility of hazardous

reactions

: Under normal conditions of storage and use, hazardous reactions will not occur.

Conditions to avoid

: Avoid all possible sources of ignition (spark or flame). Do not pressurize, cut, weld,

braze, solder, drill, grind or expose containers to heat or sources of ignition.

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

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Section 10. Stability and reactivity

Incompatible materials

: Oxidizers and Yellow Metals (brass & copper)

Hazardous decomposition

products

: Under normal conditions of storage and use, hazardous decomposition products should

not be produced.

Hazardous polymerization

: Under normal conditions of storage and use, hazardous polymerization will not occur.

Section 11. Toxicological information

Information on toxicological effects

Acute toxicity

Product/ingredient name

Result

Species

Dose

Exposure

ammonia

LC50 Inhalation Gas.

Rat

7338 ppm

1 hours

Irritation/Corrosion

Not available.

Sensitization

Not available.

Mutagenicity

Not available.

Carcinogenicity

Not available.

Reproductive toxicity

Not available.

Teratogenicity

Not available.

Specific target organ toxicity (single exposure)

Not available.

Specific target organ toxicity (repeated exposure)

Not available.

Aspiration hazard

Not available.

Information on the likely

routes of exposure

: Not available.

Potential acute health effects

Eye contact

: Causes serious eye damage.

: Harmful if inhaled.

Inhalation

Skin contact

: Causes severe burns.

Ingestion

: As this product is a gas, refer to the inhalation section.

Symptoms related to the physical, chemical and toxicological characteristics

Eye contact

Inhalation

: Adverse symptoms may include the following:, pain, watering, redness

: No specific data.

Skin contact

: Adverse symptoms may include the following:, pain or irritation, redness, blistering may

occur

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

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Section 11. Toxicological information

Ingestion

: Adverse symptoms may include the following:, stomach pains

Delayed and immediate effects and also chronic effects from short and long term exposure

Short term exposure

Potential immediate

effects

: Not available.

Potential delayed effects : Not available.

Long term exposure

Potential immediate

effects

: Not available.

Potential delayed effects : Not available.

Potential chronic health effects

Not available.

General

: No known significant effects or critical hazards.

Carcinogenicity

Mutagenicity

: No known significant effects or critical hazards.

Teratogenicity

Developmental effects

Fertility effects

Numerical measures of toxicity

Acute toxicity estimates

Not available.

Other information

: IDLH : 300 ppm

Section 12. Ecological information

Toxicity

Product/ingredient name

Result

Species

Exposure

ammonia

Acute EC50 29.2 mg/l Marine water

Acute LC50 2080 µg/l Fresh water

Acute LC50 0.53 ppm Fresh water

Acute LC50 300 µg/l Fresh water

Algae - Ulva fasciata - Zoea

96 hours

Crustaceans - Gammarus pulex 48 hours

Daphnia - Daphnia magna 48 hours

Fish - Hypophthalmichthys nobilis 96 hours

Chronic NOEC 0.204 mg/l Marine water Fish - Dicentrarchus labrax

62 days

Persistence and degradability

Not available.

Bioaccumulative potential

Not available.

Mobility in soil

Soil/water partition

coefficient (K_OC)

: Not available.

Other adverse effects

: No known significant effects or critical hazards.

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

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Section 13. Disposal considerations

Disposal methods

: The generation of waste should be avoided or minimized wherever possible. Disposal

of this product, solutions and any by-products should at all times comply with the

requirements of environmental protection and waste disposal legislation and any

regional local authority requirements. Dispose of surplus and non-recyclable products

via a licensed waste disposal contractor. Waste should not be disposed of untreated to

the sewer unless fully compliant with the requirements of all authorities with jurisdiction.

Empty Airgas-owned pressure vessels should be returned to Airgas. Waste packaging

should be recycled. Incineration or landfill should only be considered when recycling is

not feasible. This material and its container must be disposed of in a safe way. Empty

containers or liners may retain some product residues. Do not puncture or incinerate

container.

Section 14. Transport information

DOT

TDG

Mexico

IMDG

IATA

UN number

UN1005

UN proper

AMMONIA,

ANHYDROUS

ANHYDROUS;

OR ANHYDROUS

AMMONIA

ANHYDROUS

shipping name

Transport

2.2

2.3 (8)

hazard class(es)

Packing group

Environmental

hazards

Yes.

Yes. The

environmentally

hazardous

Yes.

Yes. The

environmentally

hazardous

substance mark is

not required.

substance mark is

not required.

“Refer to CFR 49 (or authority having jurisdiction) to determine the information required for shipment of the

product.”

Additional information

DOT Classification

Inhalation hazard

This product is not regulated as a marine pollutant when transported on inland

waterways in sizes of ≤5 L or ≤5 kg or by road, rail, or inland air in non-bulk sizes,

provided the packagings meet the general provisions of §§ 173.24 and 173.24a.

Reportable quantity

100 lbs / 45.4 kg. Package sizes shipped in quantities less than

the product reportable quantity are not subject to the RQ (reportable quantity)

transportation requirements.

Limited quantity

Yes.

Quantity limitation

Special provisions

Passenger aircraft/rail: Forbidden. Cargo aircraft: Forbidden.

13,T50

TDG Classification

Product classified as per the following sections of the Transportation of Dangerous

Goods Regulations: 2.13-2.17 (Class 2), 2.40-2.42 (Class 8), 2.7 (Marine pollutant

mark).

The marine pollutant mark is not required when transported by road or rail.

Explosive Limit and Limited Quantity Index

ERAP Index

3000

Passenger Carrying Ship Index

Forbidden

Passenger Carrying Road or Rail Index

Forbidden

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

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Section 14. Transport information

Special provisions

Mexico Classification

: Toxic Inhalation Hazard Zone D

: The marine pollutant mark is not required when transported in sizes of ≤5 L or ≤5 kg.

IMDG

IATA

The environmentally hazardous substance mark may appear if required by other

transportation regulations.

Quantity limitation

Passenger and Cargo Aircraft: Forbidden. Cargo Aircraft Only:

Forbidden. Limited Quantities - Passenger Aircraft: Forbidden.

Special precautions for user : Transport within user’s premises:

always transport in closed containers that are

upright and secure. Ensure that persons transporting the product know what to do in the

event of an accident or spillage.

Transport in bulk according : Not available.

to Annex II of MARPOL and

the IBC Code

Section 15. Regulatory information

U.S. Federal regulations

: TSCA 8(a) CDR Exempt/Partial exemption

: Not determined

Clean Water Act (CWA) 311

: ammonia

Clean Air Act (CAA) 112 regulated toxic substances

: ammonia

Clean Air Act Section 112 : Not listed

(b) Hazardous Air

Pollutants (HAPs)

Clean Air Act Section 602

Class I Substances

: Not listed

Clean Air Act Section 602

Class II Substances

DEA List I Chemicals

(Precursor Chemicals)

DEA List II Chemicals

(Essential Chemicals)

SARA 302/304

Composition/information on ingredients

SARA 302 TPQ

EHS (lbs) (gallons)

Yes. 500

SARA 304 RQ

Name

(lbs)

(gallons)

ammonia

100

SARA 304 RQ

SARA 311/312

Classification

SARA 313

: 100 lbs / 45.4 kg

: Refer to Section 2: Hazards Identification of this SDS for classification of substance.

Product name

CAS number

ammonia

7664-41-7

100

Form R - Reporting

requirements

ammonia

7664-41-7

100

Supplier notification

SARA 313 notifications must not be detached from the SDS and any copying and redistribution of the SDS shall include

copying and redistribution of the notice attached to copies of the SDS subsequently redistributed.

State regulations

Massachusetts

: This material is listed.

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

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Section 15. Regulatory information

New York

: This material is listed.

New Jersey

Pennsylvania

International regulations

Chemical Weapon Convention List Schedules I, II & III Chemicals

Not listed.

Montreal Protocol (Annexes A, B, C, E)

Not listed.

Stockholm Convention on Persistent Organic Pollutants

Not listed.

Rotterdam Convention on Prior Informed Consent (PIC)

Not listed.

UNECE Aarhus Protocol on POPs and Heavy Metals

Not listed.

Inventory list

Australia

Canada

China

: This material is listed or exempted.

Europe

Japan

: Japan inventory (ENCS)

Japan inventory (ISHL)

: This material is listed or exempted.

Malaysia

: This material is listed or exempted.

: Not determined.

New Zealand

Philippines

Republic of Korea

Taiwan

Thailand

Turkey

: This material is listed or exempted.

: Not determined.

United States

Viet Nam

Section 16. Other information

Hazardous Material Information System (U.S.A.)

Health

Flammability

Physical hazards

Caution: HMIS® ratings are based on a 0-4 rating scale, with 0 representing minimal hazards or risks, and 4

representing significant hazards or risks. Although HMIS® ratings and the associated label are not required on

SDSs or products leaving a facility under 29 CFR 1910.1200, the preparer may choose to provide them. HMIS®

ratings are to be used with a fully implemented HMIS® program. HMIS® is a registered trademark and service

mark of the American Coatings Association, Inc.

The customer is responsible for determining the PPE code for this material. For more information on HMIS®

Personal Protective Equipment (PPE) codes, consult the HMIS® Implementation Manual.

National Fire Protection Association (U.S.A.)

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

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Section 16. Other information

Flammability

Health

Instability/Reactivity

Special

Reprinted with permission from NFPA 704-2001, Identification of the Hazards of Materials for Emergency

not the complete and official position of the National Fire Protection Association, on the referenced subject

which is represented only by the standard in its entirety.

be interpreted and applied only by properly trained individuals to identify fire, health and reactivity hazards of

chemicals. The user is referred to certain limited number of chemicals with recommended classifications in

NFPA 49 and NFPA 325, which would be used as a guideline only. Whether the chemicals are classified by NFPA

or not, anyone using the 704 systems to classify chemicals does so at their own risk.

Procedure used to derive the classification

Classification

Justification

Expert judgment

FLAMMABLE GASES - Category 2

GASES UNDER PRESSURE - Liquefied gas

ACUTE TOXICITY (inhalation) - Category 4

SKIN CORROSION - Category 1

SERIOUS EYE DAMAGE - Category 1

AQUATIC HAZARD (ACUTE) - Category 1

Expert judgment

History

Date of printing

: 2/15/2018

Date of issue/Date of

revision

Date of previous issue

Version

: 2/15/2018

: 1.04

Key to abbreviations

: ATE = Acute Toxicity Estimate

BCF = Bioconcentration Factor

GHS = Globally Harmonized System of Classification and Labelling of Chemicals

IATA = International Air Transport Association

IBC = Intermediate Bulk Container

IMDG = International Maritime Dangerous Goods

LogPow = logarithm of the octanol/water partition coefficient

MARPOL = International Convention for the Prevention of Pollution From Ships, 1973

as modified by the Protocol of 1978. ("Marpol" = marine pollution)

UN = United Nations

References

: Not available.

Notice to reader

To the best of our knowledge, the information contained herein is accurate. However, neither the above-named

supplier, nor any of its subsidiaries, assumes any liability whatsoever for the accuracy or completeness of the

information contained herein.

Final determination of suitability of any material is the sole responsibility of the user. All materials may present

unknown hazards and should be used with caution. Although certain hazards are described herein, we cannot

guarantee that these are the only hazards that exist.

Date of issue/Date of revision

: 2/15/2018

Date of previous issue

: 2/15/2018

Version : 1.04

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